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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/34\">Codeforces Beta Round 34 (Div. 2)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='581c8093391551f817561e73b26e6367'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/34/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Greedy algorithms\">\r\n greedy\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Sortings, orderings\">\r\n sortings\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *900\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='581c8093391551f817561e73b26e6367'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"160\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='581c8093391551f817561e73b26e6367'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"160\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, 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Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/746\" title=\"Codeforces Beta Round #34 (Div. 2)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"143:144\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/748\" title=\"Codeforces Beta Round #34 (Div. 2) Разбор\" target=\"_blank\">Tutorial <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"525\" resourceName=\"Codeforces Beta Round #34 (Div. 2) Разбор\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/34\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/34/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/34/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/34/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/34/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/34/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/34/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/34/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"B\" data-uuid=\"ps_2e802351fcaed6fff37790c722f00d8715e2a3dd\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Sale</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Once Bob got to a sale of old TV sets. There were <span class=\"tex-span\"><i>n</i></span> TV sets at that sale. TV set with index <span class=\"tex-span\"><i>i</i></span> costs <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> bellars. Some TV sets have a negative price — their owners are ready to pay Bob if he buys their useless apparatus. Bob can «buy» any TV sets he wants. Though he's very strong, Bob can carry at most <span class=\"tex-span\"><i>m</i></span> TV sets, and he has no desire to go to the sale for the second time. Please, help Bob find out the maximum sum of money that he can earn.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two space-separated integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">1 ≤ <i>m</i> ≤ <i>n</i> ≤ 100</span>) — amount of TV sets at the sale, and amount of TV sets that Bob can carry. The following line contains <span class=\"tex-span\"><i>n</i></span> space-separated integers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\"> - 1000 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 1000</span>) — prices of the TV sets. </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the only number — the maximum sum of money that Bob can earn, given that he can carry at most <span class=\"tex-span\"><i>m</i></span> TV sets.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5 3<br />-6 0 35 -2 4<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>8<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 2<br />7 0 0 -7<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>7<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=B]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if (result[\"success\"] === \"true\") {\r\n Codeforces.facebox(\".diff-popup\", \"//codeforces.org/s/73366\");\r\n 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='1728cbaec0e8d4cfb09d299a33fc492a'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n </label>\r\n </div>\r\n <div style=\"padding: 0 1em 1em 1em;text-align:right;\">\r\n <input style=\"height:1.65em;padding:0 0.75em;\" type=\"submit\" value=\"Find\"/>\r\n </div>\r\n </form>\r\n </div>\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".handleBox\").autocomplete(\"/data/handles\", {\r\n delay: 200,\r\n width: 200,\r\n selectFirst: false,\r\n matchContains: true,\r\n minChars: 3\r\n });\r\n $(\".handleForm\").attr(\"autocomplete\", \"off\").submit(function () {\r\n var link = \"/profile/userHandle\".replace(\r\n \"userHandle\", $(this).find(\".handleBox\").val()\r\n );\r\n window.location = link;\r\n return false;\r\n });\r\n });\n </script>\n\r\n\r\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Recent actions\n <div class=\"top-links\">\n </div>\n </div>\n <div class=\"recent-actions\">\r\n <ul>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a href=\"/blog/entry/121171\">An Interesting Tree Problem</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/.Danet\" title=\"Expert .Danet\" class=\"rated-user user-blue\">.Danet</a> →\r\n <a href=\"/blog/entry/121172\">[TLE on pretest1]</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/sszcdjr\" title=\"Master sszcdjr\" class=\"rated-user user-orange\">sszcdjr</a> →\r\n <a href=\"/blog/entry/119859\">Codeforces Round 896 (Div. 1, Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" 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Это мой первый разбор, просьба сильно не пинать. =)<div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">A. Разведка 2</span></div></div><div>Нахождение минимума в массиве, с одим дополнительным сравнением первого и последнего элементов.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">B. Распродажа</span><br /></div><div>Отрицательные элементы складываем в массив, сортируем, находим сумму m наибольших по модулю.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">C. Список</span><br /></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\">Решается массивом булей, единственная заковыка - с выводом, но вполне преодолима.</span><br /></span></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\"><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">D. Карта дорог</span><br /></span></span></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\"><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><font><span style=\"line-height: normal;font-size: medium;\">Создаем динамическую матрицу смежности, например, массивом стеков, заполняем.</span></font></span></span></span> Потом волновым алгоритмом из r<sub>2</sub>, пробегаясь по каждой вершине один раз, пролучаем результирующий массив.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">E. Столкновения</span></div><div>Заведем переменную времени ct, которая вначале равна 0.</div><div>Начинаем моделировать:</div><div>Пусть dt равен t - ct, просматриваем все пары шариков, по формуле </div><div>x<sub>1</sub> + v<sub>1 </sub>* dt = x<sub>2</sub> + v<sub>2</sub> * dt</div><div>dt = (x<sub>1</sub> - x<sub>2</sub>) / (v<sub>2</sub> - v<sub>1</sub>)</div><div>находим минимальную dt - промежуток времени, через который какие-нибудь шарики столкнуться, или время моделирования закончится.</div><div>Сдвигаем шарики на этот промежуток времени, снова просматриваем все пары, если координаты двух совпадают, меняем их скорости по формуле из условия.</div><div>Повторять, пока ct не сравняется с t.</div><div>Особое внимание стоит уделить точности, наверное на этом и подловили RAVEman'а с ACRush'ем. =)</div><div>В принятом решении я использовал double и точность сравнений 10<sup>-10</sup>.</div><div><br /></div><div>Удачи в контестах!</div></div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2252-748\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2252\",\n blogEntryId: \"748\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+34\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 34</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces формат</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-748\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:gray'>-5</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-748\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/Abra\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/Abra\">\n Abra\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/11/2010 20:53\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/748#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/748#comments\">\n 4\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"758\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (2)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"742295\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/www.___.com\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/www.___.com\" title=\"Unrated, www.___.com\" class=\"rated-user user-black\">www.___.com</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/02/2021 21:41\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-742295\" href=\"?#comment-742295\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"742295\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"1808549\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-742295\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Tutorial for <a href=\"https://codeforces.com/contest/34/problem/D\">CF 34D Road Map</a></p> <div class=\"spoiler\"><b class=\"spoiler-title\">Spoiler</b><div class=\"spoiler-content\" style=\"display: none;\"><p>In this problem, the root of the tree is $$$r_1$$$. Suppose you want to go to an arbitrary node $$$x$$$ from the root $$$r_1$$$ and the last city on the way to go to $$$x$$$ is $$$y$$$, then $$$y$$$ is the $$$parent$$$ of $$$x$$$. It is true because the nearest node in the way to go the $$$root$$$ from an arbitrary node is it's $$$parent$$$. But the question is how can we get the whole tree? It is possible because you are getting the $$$parents$$$ for all nodes which is enough to build a tree. </p><p>Now you can see that, the problem has became <strong>'Change the root from $$$r_1$$$ to $$$r_2$$$ and then find the parents for all nodes.'</strong> So we can run a DFS from the new root $$$r_2$$$ to find the parents for all nodes.</p><p>Sorry for my poor English.</p></div></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-742295 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-742295 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-742295\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"876662\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/sugam10\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/sugam10\" title=\"Specialist sugam10\" class=\"rated-user user-cyan\">sugam10</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/11/2022 15:09\">21 month(s) ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-876662\" href=\"?#comment-876662\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"876662\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1722742\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-876662\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>code for problem D Road Map` <a href=\"/contest/34/submission/142366754\" title=\"Submission 142366754 by sugam10\">142366754</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-876662 en 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style=\"display: none;\">\r\n <div class=\"up dir\" title=\"Ctrl+Up\">↑<hr/>\r\n </div>\r\n <div class=\"info\" title=\"New comments\"></div>\r\n <div class=\"down dir\" title=\"Ctrl+Down\">\r\n <hr/>↓\r\n </div>\r\n </div>\r\n\r\n <script>\r\n $(\".show-archived-checkbox\").change(function () {\r\n const checked = $(this).is(\":checked\");\r\n $.post(\"/data/comment-data\", {action: \"setShowArchived\", checked}, function (json) {\r\n if (json[\"success\"] !== \"true\") {\r\n alert(json[\"error\"]);\r\n } else {\r\n if (checked) {\r\n Codeforces.reloadAndShowMessage(\"Archived comments are now displayed\")\r\n } else {\r\n Codeforces.reloadAndShowMessage(\"Archived comments are no longer displayed\")\r\n }\r\n }\r\n });\r\n return false;\r\n });\r\n\r\n function gotoComment(direction) {\r\n var box = $(\".new-comments-box\");\r\n var index = parseInt(box.attr(\"data-index\"));\r\n if (index == -1)\r\n index = 0;\r\n else\r\n index = Math.max(0, 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Page Numbers"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Page Numbers</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>«Bersoft» company is working on a new version of its most popular text editor — Bord 2010. Bord, like many other text editors, should be able to print out multipage documents. A user keys a sequence of the document page numbers that he wants to print out (separates them with a comma, without spaces).</p><p>Your task is to write a part of the program, responsible for «standardization» of this sequence. Your program gets the sequence, keyed by the user, as input. The program should output this sequence in format <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\">1</sub></span>-<span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span>,<span class=\"tex-span\"><i>l</i><sub class=\"lower-index\">2</sub></span>-<span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">2</sub></span>,...,<span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>k</i></sub></span>-<span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>k</i></sub></span>, where <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub> + 1 < <i>l</i><sub class=\"lower-index\"><i>i</i> + 1</sub></span> for all <span class=\"tex-span\"><i>i</i></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>k</i> - 1</span>, and <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>. The new sequence should contain all the page numbers, keyed by the user, and nothing else. If some page number appears in the input sequence several times, its appearances, starting from the second one, should be ignored. If for some element <span class=\"tex-span\"><i>i</i></span> from the new sequence <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub> = <i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>, this element should be output as <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span>, and not as «<span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub> - <i>l</i><sub class=\"lower-index\"><i>i</i></sub></span>».</p><p>For example, sequence <span class=\"tex-font-style-tt\">1,2,3,1,1,2,6,6,2</span> should be output as <span class=\"tex-font-style-tt\">1-3,6</span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The only line contains the sequence, keyed by the user. The sequence contains at least one and at most 100 positive integer numbers. It's guaranteed, that this sequence consists of positive integer numbers, not exceeding 1000, separated with a comma, doesn't contain any other characters, apart from digits and commas, can't end with a comma, and the numbers don't contain leading zeroes. Also it doesn't start with a comma or contain more than one comma in a row.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the sequence in the required format.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1,2,3,1,1,2,6,6,2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1-3,6<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3,2,1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1-3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>30,20,10<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>10,20,30<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"7355f40b32f9c3c1d93030515186969e\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"1b8bc39679008392204e3fdf9d5bf2b6ae394d10\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"C\" data-uuid=\"ps_081341814e90dbe5afc172b2cb0f72dd8f68b028\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Page Numbers</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>«Bersoft» company is working on a new version of its most popular text editor — Bord 2010. Bord, like many other text editors, should be able to print out multipage documents. A user keys a sequence of the document page numbers that he wants to print out (separates them with a comma, without spaces).</p><p>Your task is to write a part of the program, responsible for «standardization» of this sequence. Your program gets the sequence, keyed by the user, as input. The program should output this sequence in format <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\">1</sub></span>-<span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span>,<span class=\"tex-span\"><i>l</i><sub class=\"lower-index\">2</sub></span>-<span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">2</sub></span>,...,<span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>k</i></sub></span>-<span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>k</i></sub></span>, where <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub> + 1 < <i>l</i><sub class=\"lower-index\"><i>i</i> + 1</sub></span> for all <span class=\"tex-span\"><i>i</i></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>k</i> - 1</span>, and <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>. The new sequence should contain all the page numbers, keyed by the user, and nothing else. If some page number appears in the input sequence several times, its appearances, starting from the second one, should be ignored. If for some element <span class=\"tex-span\"><i>i</i></span> from the new sequence <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub> = <i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>, this element should be output as <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span>, and not as «<span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub> - <i>l</i><sub class=\"lower-index\"><i>i</i></sub></span>».</p><p>For example, sequence <span class=\"tex-font-style-tt\">1,2,3,1,1,2,6,6,2</span> should be output as <span class=\"tex-font-style-tt\">1-3,6</span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The only line contains the sequence, keyed by the user. The sequence contains at least one and at most 100 positive integer numbers. It's guaranteed, that this sequence consists of positive integer numbers, not exceeding 1000, separated with a comma, doesn't contain any other characters, apart from digits and commas, can't end with a comma, and the numbers don't contain leading zeroes. Also it doesn't start with a comma or contain more than one comma in a row.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the sequence in the required format.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1,2,3,1,1,2,6,6,2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1-3,6<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3,2,1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1-3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>30,20,10<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>10,20,30<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:10</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='1728cbaec0e8d4cfb09d299a33fc492a'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/Abra\">Abra</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/Abra\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/Abra\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/Abra\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/Abra\">Contests</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/Abra\" style=\"text-decoration:none;color:black !important;\">Abra's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"748\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/748\"> Codeforces Beta Round #34 (Div. 2) Разбор\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/Abra\" title=\"Candidate Master Abra\" class=\"rated-user user-violet\">Abra</a>,\r\n <span class=\"format-humantime\" title=\"Oct/11/2010 20:53\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">Привет, мир! Это мой первый разбор, просьба сильно не пинать. =)<div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">A. Разведка 2</span></div></div><div>Нахождение минимума в массиве, с одим дополнительным сравнением первого и последнего элементов.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">B. Распродажа</span><br /></div><div>Отрицательные элементы складываем в массив, сортируем, находим сумму m наибольших по модулю.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">C. Список</span><br /></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\">Решается массивом булей, единственная заковыка - с выводом, но вполне преодолима.</span><br /></span></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\"><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">D. Карта дорог</span><br /></span></span></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\"><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><font><span style=\"line-height: normal;font-size: medium;\">Создаем динамическую матрицу смежности, например, массивом стеков, заполняем.</span></font></span></span></span> Потом волновым алгоритмом из r<sub>2</sub>, пробегаясь по каждой вершине один раз, пролучаем результирующий массив.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">E. Столкновения</span></div><div>Заведем переменную времени ct, которая вначале равна 0.</div><div>Начинаем моделировать:</div><div>Пусть dt равен t - ct, просматриваем все пары шариков, по формуле </div><div>x<sub>1</sub> + v<sub>1 </sub>* dt = x<sub>2</sub> + v<sub>2</sub> * dt</div><div>dt = (x<sub>1</sub> - x<sub>2</sub>) / (v<sub>2</sub> - v<sub>1</sub>)</div><div>находим минимальную dt - промежуток времени, через который какие-нибудь шарики столкнуться, или время моделирования закончится.</div><div>Сдвигаем шарики на этот промежуток времени, снова просматриваем все пары, если координаты двух совпадают, меняем их скорости по формуле из условия.</div><div>Повторять, пока ct не сравняется с t.</div><div>Особое внимание стоит уделить точности, наверное на этом и подловили RAVEman'а с ACRush'ем. =)</div><div>В принятом решении я использовал double и точность сравнений 10<sup>-10</sup>.</div><div><br /></div><div>Удачи в контестах!</div></div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2252-748\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2252\",\n blogEntryId: \"748\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+34\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 34</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces формат</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-748\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:gray'>-5</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-748\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/Abra\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/Abra\">\n Abra\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/11/2010 20:53\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/748#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/748#comments\">\n 4\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"758\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (2)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"742295\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/www.___.com\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/www.___.com\" title=\"Unrated, www.___.com\" class=\"rated-user user-black\">www.___.com</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/02/2021 21:41\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-742295\" href=\"?#comment-742295\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"742295\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"1808549\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-742295\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Tutorial for <a href=\"https://codeforces.com/contest/34/problem/D\">CF 34D Road Map</a></p> <div class=\"spoiler\"><b class=\"spoiler-title\">Spoiler</b><div class=\"spoiler-content\" style=\"display: none;\"><p>In this problem, the root of the tree is $$$r_1$$$. Suppose you want to go to an arbitrary node $$$x$$$ from the root $$$r_1$$$ and the last city on the way to go to $$$x$$$ is $$$y$$$, then $$$y$$$ is the $$$parent$$$ of $$$x$$$. It is true because the nearest node in the way to go the $$$root$$$ from an arbitrary node is it's $$$parent$$$. But the question is how can we get the whole tree? It is possible because you are getting the $$$parents$$$ for all nodes which is enough to build a tree. </p><p>Now you can see that, the problem has became <strong>'Change the root from $$$r_1$$$ to $$$r_2$$$ and then find the parents for all nodes.'</strong> So we can run a DFS from the new root $$$r_2$$$ to find the parents for all nodes.</p><p>Sorry for my poor English.</p></div></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-742295 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-742295 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-742295\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"876662\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/sugam10\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/sugam10\" title=\"Specialist sugam10\" class=\"rated-user user-cyan\">sugam10</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/11/2022 15:09\">21 month(s) ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-876662\" href=\"?#comment-876662\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"876662\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1722742\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-876662\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>code for problem D Road Map` <a href=\"/contest/34/submission/142366754\" title=\"Submission 142366754 by sugam10\">142366754</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-876662 en 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Road Map"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Road Map</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>There are <span class=\"tex-span\"><i>n</i></span> cities in Berland. Each city has its index — an integer number from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>. The capital has index <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span>. All the roads in Berland are two-way. The road system is such that there is exactly one path from the capital to each city, i.e. the road map looks like a tree. In Berland's chronicles the road map is kept in the following way: for each city <span class=\"tex-span\"><i>i</i></span>, different from the capital, there is kept number <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span> — index of the last city on the way from the capital to <span class=\"tex-span\"><i>i</i></span>.</p><p>Once the king of Berland Berl XXXIV decided to move the capital from city <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span> to city <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">2</sub></span>. Naturally, after this the old representation of the road map in Berland's chronicles became incorrect. Please, help the king find out a new representation of the road map in the way described above.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three space-separated integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">2</sub></span> (<span class=\"tex-span\">2 ≤ <i>n</i> ≤ 5·10<sup class=\"upper-index\">4</sup>, 1 ≤ <i>r</i><sub class=\"lower-index\">1</sub> ≠ <i>r</i><sub class=\"lower-index\">2</sub> ≤ <i>n</i></span>) — amount of cities in Berland, index of the old capital and index of the new one, correspondingly.</p><p>The following line contains <span class=\"tex-span\"><i>n</i> - 1</span> space-separated integers — the old representation of the road map. For each city, apart from <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span>, there is given integer <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span> — index of the last city on the way from the capital to city <span class=\"tex-span\"><i>i</i></span>. All the cities are described in order of increasing indexes.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output <span class=\"tex-span\"><i>n</i> - 1</span> numbers — new representation of the road map in the same format.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 2 3<br/>2 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 3 </pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>6 2 4<br/>6 1 2 4 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6 4 1 4 2 </pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"1066f0dbc55e594859dae1decba04385\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"1b8bc39679008392204e3fdf9d5bf2b6ae394d10\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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|| c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_9eb235cd6db9dfe5825b5e93f490f6fc920b3f14\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Road Map</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>There are <span class=\"tex-span\"><i>n</i></span> cities in Berland. Each city has its index — an integer number from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>. The capital has index <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span>. All the roads in Berland are two-way. The road system is such that there is exactly one path from the capital to each city, i.e. the road map looks like a tree. In Berland's chronicles the road map is kept in the following way: for each city <span class=\"tex-span\"><i>i</i></span>, different from the capital, there is kept number <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span> — index of the last city on the way from the capital to <span class=\"tex-span\"><i>i</i></span>.</p><p>Once the king of Berland Berl XXXIV decided to move the capital from city <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span> to city <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">2</sub></span>. Naturally, after this the old representation of the road map in Berland's chronicles became incorrect. Please, help the king find out a new representation of the road map in the way described above.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three space-separated integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">2</sub></span> (<span class=\"tex-span\">2 ≤ <i>n</i> ≤ 5·10<sup class=\"upper-index\">4</sup>, 1 ≤ <i>r</i><sub class=\"lower-index\">1</sub> ≠ <i>r</i><sub class=\"lower-index\">2</sub> ≤ <i>n</i></span>) — amount of cities in Berland, index of the old capital and index of the new one, correspondingly.</p><p>The following line contains <span class=\"tex-span\"><i>n</i> - 1</span> space-separated integers — the old representation of the road map. For each city, apart from <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\">1</sub></span>, there is given integer <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span> — index of the last city on the way from the capital to city <span class=\"tex-span\"><i>i</i></span>. All the cities are described in order of increasing indexes.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output <span class=\"tex-span\"><i>n</i> - 1</span> numbers — new representation of the road map in the same format.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 2 3<br />2 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 3 </pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>6 2 4<br />6 1 2 4 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6 4 1 4 2 </pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:10</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='1728cbaec0e8d4cfb09d299a33fc492a'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/Abra\">Abra</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/Abra\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/Abra\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/Abra\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/Abra\">Contests</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/Abra\" style=\"text-decoration:none;color:black !important;\">Abra's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"748\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/748\"> Codeforces Beta Round #34 (Div. 2) Разбор\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/Abra\" title=\"Candidate Master Abra\" class=\"rated-user user-violet\">Abra</a>,\r\n <span class=\"format-humantime\" title=\"Oct/11/2010 20:53\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">Привет, мир! Это мой первый разбор, просьба сильно не пинать. =)<div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">A. Разведка 2</span></div></div><div>Нахождение минимума в массиве, с одим дополнительным сравнением первого и последнего элементов.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">B. Распродажа</span><br /></div><div>Отрицательные элементы складываем в массив, сортируем, находим сумму m наибольших по модулю.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">C. Список</span><br /></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\">Решается массивом булей, единственная заковыка - с выводом, но вполне преодолима.</span><br /></span></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\"><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">D. Карта дорог</span><br /></span></span></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\"><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><font><span style=\"line-height: normal;font-size: medium;\">Создаем динамическую матрицу смежности, например, массивом стеков, заполняем.</span></font></span></span></span> Потом волновым алгоритмом из r<sub>2</sub>, пробегаясь по каждой вершине один раз, пролучаем результирующий массив.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">E. Столкновения</span></div><div>Заведем переменную времени ct, которая вначале равна 0.</div><div>Начинаем моделировать:</div><div>Пусть dt равен t - ct, просматриваем все пары шариков, по формуле </div><div>x<sub>1</sub> + v<sub>1 </sub>* dt = x<sub>2</sub> + v<sub>2</sub> * dt</div><div>dt = (x<sub>1</sub> - x<sub>2</sub>) / (v<sub>2</sub> - v<sub>1</sub>)</div><div>находим минимальную dt - промежуток времени, через который какие-нибудь шарики столкнуться, или время моделирования закончится.</div><div>Сдвигаем шарики на этот промежуток времени, снова просматриваем все пары, если координаты двух совпадают, меняем их скорости по формуле из условия.</div><div>Повторять, пока ct не сравняется с t.</div><div>Особое внимание стоит уделить точности, наверное на этом и подловили RAVEman'а с ACRush'ем. =)</div><div>В принятом решении я использовал double и точность сравнений 10<sup>-10</sup>.</div><div><br /></div><div>Удачи в контестах!</div></div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2252-748\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2252\",\n blogEntryId: \"748\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+34\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 34</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces формат</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-748\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:gray'>-5</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-748\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/Abra\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/Abra\">\n Abra\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/11/2010 20:53\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/748#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/748#comments\">\n 4\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"758\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (2)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"742295\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/www.___.com\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/www.___.com\" title=\"Unrated, www.___.com\" class=\"rated-user user-black\">www.___.com</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/02/2021 21:41\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-742295\" href=\"?#comment-742295\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"742295\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"1808549\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-742295\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Tutorial for <a href=\"https://codeforces.com/contest/34/problem/D\">CF 34D Road Map</a></p> <div class=\"spoiler\"><b class=\"spoiler-title\">Spoiler</b><div class=\"spoiler-content\" style=\"display: none;\"><p>In this problem, the root of the tree is $$$r_1$$$. Suppose you want to go to an arbitrary node $$$x$$$ from the root $$$r_1$$$ and the last city on the way to go to $$$x$$$ is $$$y$$$, then $$$y$$$ is the $$$parent$$$ of $$$x$$$. It is true because the nearest node in the way to go the $$$root$$$ from an arbitrary node is it's $$$parent$$$. But the question is how can we get the whole tree? It is possible because you are getting the $$$parents$$$ for all nodes which is enough to build a tree. </p><p>Now you can see that, the problem has became <strong>'Change the root from $$$r_1$$$ to $$$r_2$$$ and then find the parents for all nodes.'</strong> So we can run a DFS from the new root $$$r_2$$$ to find the parents for all nodes.</p><p>Sorry for my poor English.</p></div></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-742295 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-742295 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-742295\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"876662\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/sugam10\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/sugam10\" title=\"Specialist sugam10\" class=\"rated-user user-cyan\">sugam10</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/11/2022 15:09\">21 month(s) ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-876662\" href=\"?#comment-876662\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"876662\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1722742\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-876662\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>code for problem D Road Map` <a href=\"/contest/34/submission/142366754\" title=\"Submission 142366754 by sugam10\">142366754</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-876662 en 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Collisions"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Collisions</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>On a number line there are <span class=\"tex-span\"><i>n</i></span> balls. At time moment <span class=\"tex-span\">0</span> for each ball the following data is known: its coordinate <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span>, speed <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\"><i>i</i></sub></span> (possibly, negative) and weight <span class=\"tex-span\"><i>m</i><sub class=\"lower-index\"><i>i</i></sub></span>. The radius of the balls can be ignored.</p><p>The balls collide elastically, i.e. if two balls weighing <span class=\"tex-span\"><i>m</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>m</i><sub class=\"lower-index\">2</sub></span> and with speeds <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\">2</sub></span> collide, their new speeds will be: </p><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ac0ba386393df0dee152978a56480d69479d3b98.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/></center>.<p>Your task is to find out, where each ball will be <span class=\"tex-span\"><i>t</i></span> seconds after.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>t</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10, 0 ≤ <i>t</i> ≤ 100</span>) — amount of balls and duration of the process. Then follow <span class=\"tex-span\"><i>n</i></span> lines, each containing three integers: <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>m</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ |<i>v</i><sub class=\"lower-index\"><i>i</i></sub>|, <i>m</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100, |<i>x</i><sub class=\"lower-index\"><i>i</i></sub>| ≤ 100</span>) — coordinate, speed and weight of the ball with index <span class=\"tex-span\"><i>i</i></span> at time moment <span class=\"tex-span\">0</span>.</p><p>It is guaranteed that no two balls have the same coordinate initially. Also each collision will be a collision of not more than two balls (that is, three or more balls never collide at the same point in all times from segment <span class=\"tex-span\">[0;<i>t</i>]</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output <span class=\"tex-span\"><i>n</i></span> numbers — coordinates of the balls <span class=\"tex-span\"><i>t</i></span> seconds after. Output the numbers accurate to at least 4 digits after the decimal point.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 9<br/>3 4 5<br/>0 7 8<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>68.538461538<br/>44.538461538<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 10<br/>1 2 3<br/>4 -5 6<br/>7 -8 9<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>-93.666666667<br/>-74.666666667<br/>-15.666666667<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"1f86ad8373e7707374a8502601e7a9d9\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"1b8bc39679008392204e3fdf9d5bf2b6ae394d10\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"E\" data-uuid=\"ps_6bcb1f4984f0a01b76c4db4c0c3c48997af3d876\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Collisions</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>On a number line there are <span class=\"tex-span\"><i>n</i></span> balls. At time moment <span class=\"tex-span\">0</span> for each ball the following data is known: its coordinate <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span>, speed <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\"><i>i</i></sub></span> (possibly, negative) and weight <span class=\"tex-span\"><i>m</i><sub class=\"lower-index\"><i>i</i></sub></span>. The radius of the balls can be ignored.</p><p>The balls collide elastically, i.e. if two balls weighing <span class=\"tex-span\"><i>m</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>m</i><sub class=\"lower-index\">2</sub></span> and with speeds <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\">2</sub></span> collide, their new speeds will be: </p><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ac0ba386393df0dee152978a56480d69479d3b98.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center>.<p>Your task is to find out, where each ball will be <span class=\"tex-span\"><i>t</i></span> seconds after.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>t</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10, 0 ≤ <i>t</i> ≤ 100</span>) — amount of balls and duration of the process. Then follow <span class=\"tex-span\"><i>n</i></span> lines, each containing three integers: <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>m</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ |<i>v</i><sub class=\"lower-index\"><i>i</i></sub>|, <i>m</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100, |<i>x</i><sub class=\"lower-index\"><i>i</i></sub>| ≤ 100</span>) — coordinate, speed and weight of the ball with index <span class=\"tex-span\"><i>i</i></span> at time moment <span class=\"tex-span\">0</span>.</p><p>It is guaranteed that no two balls have the same coordinate initially. Also each collision will be a collision of not more than two balls (that is, three or more balls never collide at the same point in all times from segment <span class=\"tex-span\">[0;<i>t</i>]</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output <span class=\"tex-span\"><i>n</i></span> numbers — coordinates of the balls <span class=\"tex-span\"><i>t</i></span> seconds after. Output the numbers accurate to at least 4 digits after the decimal point.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 9<br />3 4 5<br />0 7 8<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>68.538461538<br />44.538461538<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 10<br />1 2 3<br />4 -5 6<br />7 -8 9<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>-93.666666667<br />-74.666666667<br />-15.666666667<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=E]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:10</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='1728cbaec0e8d4cfb09d299a33fc492a'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/Abra\">Abra</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/Abra\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/Abra\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/Abra\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/Abra\">Contests</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/Abra\" style=\"text-decoration:none;color:black !important;\">Abra's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"748\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/748\"> Codeforces Beta Round #34 (Div. 2) Разбор\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/Abra\" title=\"Candidate Master Abra\" class=\"rated-user user-violet\">Abra</a>,\r\n <span class=\"format-humantime\" title=\"Oct/11/2010 20:53\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">Привет, мир! Это мой первый разбор, просьба сильно не пинать. =)<div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">A. Разведка 2</span></div></div><div>Нахождение минимума в массиве, с одим дополнительным сравнением первого и последнего элементов.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">B. Распродажа</span><br /></div><div>Отрицательные элементы складываем в массив, сортируем, находим сумму m наибольших по модулю.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">C. Список</span><br /></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\">Решается массивом булей, единственная заковыка - с выводом, но вполне преодолима.</span><br /></span></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\"><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">D. Карта дорог</span><br /></span></span></div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><span style=\"font-family: "Times New Roman";line-height: normal;font-size: medium;\"><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\"><font><span style=\"line-height: normal;font-size: medium;\">Создаем динамическую матрицу смежности, например, массивом стеков, заполняем.</span></font></span></span></span> Потом волновым алгоритмом из r<sub>2</sub>, пробегаясь по каждой вершине один раз, пролучаем результирующий массив.</div><div><span style=\"font-family: arial;font-size: 21.0px;line-height: 21.0px;\">E. Столкновения</span></div><div>Заведем переменную времени ct, которая вначале равна 0.</div><div>Начинаем моделировать:</div><div>Пусть dt равен t - ct, просматриваем все пары шариков, по формуле </div><div>x<sub>1</sub> + v<sub>1 </sub>* dt = x<sub>2</sub> + v<sub>2</sub> * dt</div><div>dt = (x<sub>1</sub> - x<sub>2</sub>) / (v<sub>2</sub> - v<sub>1</sub>)</div><div>находим минимальную dt - промежуток времени, через который какие-нибудь шарики столкнуться, или время моделирования закончится.</div><div>Сдвигаем шарики на этот промежуток времени, снова просматриваем все пары, если координаты двух совпадают, меняем их скорости по формуле из условия.</div><div>Повторять, пока ct не сравняется с t.</div><div>Особое внимание стоит уделить точности, наверное на этом и подловили RAVEman'а с ACRush'ем. =)</div><div>В принятом решении я использовал double и точность сравнений 10<sup>-10</sup>.</div><div><br /></div><div>Удачи в контестах!</div></div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2252-748\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2252\",\n blogEntryId: \"748\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+34\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 34</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces формат</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-748\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:gray'>-5</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-748\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/Abra\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/Abra\">\n Abra\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/11/2010 20:53\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/748#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/748#comments\">\n 4\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"758\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (2)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"742295\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/www.___.com\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/www.___.com\" title=\"Unrated, www.___.com\" class=\"rated-user user-black\">www.___.com</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/02/2021 21:41\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-742295\" href=\"?#comment-742295\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"742295\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"1808549\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-742295\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Tutorial for <a href=\"https://codeforces.com/contest/34/problem/D\">CF 34D Road Map</a></p> <div class=\"spoiler\"><b class=\"spoiler-title\">Spoiler</b><div class=\"spoiler-content\" style=\"display: none;\"><p>In this problem, the root of the tree is $$$r_1$$$. Suppose you want to go to an arbitrary node $$$x$$$ from the root $$$r_1$$$ and the last city on the way to go to $$$x$$$ is $$$y$$$, then $$$y$$$ is the $$$parent$$$ of $$$x$$$. It is true because the nearest node in the way to go the $$$root$$$ from an arbitrary node is it's $$$parent$$$. But the question is how can we get the whole tree? It is possible because you are getting the $$$parents$$$ for all nodes which is enough to build a tree. </p><p>Now you can see that, the problem has became <strong>'Change the root from $$$r_1$$$ to $$$r_2$$$ and then find the parents for all nodes.'</strong> So we can run a DFS from the new root $$$r_2$$$ to find the parents for all nodes.</p><p>Sorry for my poor English.</p></div></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-742295 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-742295 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-742295\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"876662\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/sugam10\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/sugam10\" title=\"Specialist sugam10\" class=\"rated-user user-cyan\">sugam10</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/11/2022 15:09\">21 month(s) ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-876662\" href=\"?#comment-876662\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"876662\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1722742\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-876662\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>code for problem D Road Map` <a href=\"/contest/34/submission/142366754\" title=\"Submission 142366754 by sugam10\">142366754</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-876662 en 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Shell Game"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Shell Game</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Today the «Z» city residents enjoy a shell game competition. The residents are gathered on the main square to watch the breath-taking performance. The performer puts 3 non-transparent cups upside down in a row. Then he openly puts a small ball under one of the cups and starts to shuffle the cups around very quickly so that on the whole he makes exactly 3 shuffles. After that the spectators have exactly one attempt to guess in which cup they think the ball is and if the answer is correct they get a prize. Maybe you can try to find the ball too?</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer from 1 to 3 — index of the cup which covers the ball before the shuffles. The following three lines describe the shuffles. Each description of a shuffle contains two distinct integers from 1 to 3 — indexes of the cups which the performer shuffled this time. The cups are numbered from left to right and are renumbered after each shuffle from left to right again. In other words, the cup on the left always has index 1, the one in the middle — index 2 and the one on the right — index 3.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output an integer from 1 to 3 — index of the cup which will have the ball after all the shuffles. </p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br/>1 2<br/>2 1<br/>2 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1<br/>2 1<br/>3 1<br/>1 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"0c073369489706e6ad4400460d8fee76\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"7003dee05763f371f54b8c55df1c6bd31fb72da1\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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}\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || 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result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_512c9c6f56ce92b72474b7bdfa8a2a9c78042577\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Shell Game</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Today the «Z» city residents enjoy a shell game competition. The residents are gathered on the main square to watch the breath-taking performance. The performer puts 3 non-transparent cups upside down in a row. Then he openly puts a small ball under one of the cups and starts to shuffle the cups around very quickly so that on the whole he makes exactly 3 shuffles. After that the spectators have exactly one attempt to guess in which cup they think the ball is and if the answer is correct they get a prize. Maybe you can try to find the ball too?</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer from 1 to 3 — index of the cup which covers the ball before the shuffles. The following three lines describe the shuffles. Each description of a shuffle contains two distinct integers from 1 to 3 — indexes of the cups which the performer shuffled this time. The cups are numbered from left to right and are renumbered after each shuffle from left to right again. In other words, the cup on the left always has index 1, the one in the middle — index 2 and the one on the right — index 3.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output an integer from 1 to 3 — index of the cup which will have the ball after all the shuffles. </p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br />1 2<br />2 1<br />2 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1<br />2 1<br />3 1<br />1 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=A]\");\r\n let uuid = 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\"*1000\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":162,"cells":{"problem_id":{"kind":"string","value":"35B"},"contest":{"kind":"string","value":"35"},"problem":{"kind":"string","value":"B"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"B. Warehouse"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Warehouse</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Once upon a time, when the world was more beautiful, the sun shone brighter, the grass was greener and the sausages tasted better Arlandia was the most powerful country. And its capital was the place where our hero DravDe worked. He couldn’t program or make up problems (in fact, few people saw a computer those days) but he was nevertheless happy. He worked in a warehouse where a magical but non-alcoholic drink Ogudar-Olok was kept. We won’t describe his work in detail and take a better look at a simplified version of the warehouse.</p><p>The warehouse has one set of shelving. It has <span class=\"tex-span\"><i>n</i></span> shelves, each of which is divided into <span class=\"tex-span\"><i>m</i></span> sections. The shelves are numbered from top to bottom starting from <span class=\"tex-span\">1</span> and the sections of each shelf are numbered from left to right also starting from <span class=\"tex-span\">1</span>. Each section can contain exactly one box of the drink, and try as he might, DravDe can never put a box in a section that already has one. In the course of his work DravDe frequently notices that he has to put a box in a filled section. In that case his solution is simple. DravDe ignores that section and looks at the next one to the right. If it is empty, he puts the box there. Otherwise he keeps looking for the first empty section to the right. If no empty section is found by the end of the shelf, he looks at the shelf which is under it, then the next one, etc. Also each time he looks at a new shelf he starts from the shelf’s beginning. If DravDe still can’t find an empty section for the box, he immediately drinks it all up and throws the empty bottles away not to be caught.</p><p>After one great party with a lot of Ogudar-Olok drunk DravDe asked you to help him. Unlike him, you can program and therefore modeling the process of counting the boxes in the warehouse will be easy work for you.</p><p>The process of counting contains two types of query messages: </p><ul> <li> «<span class=\"tex-font-style-bf\"><span class=\"tex-font-style-tt\">+1 x y id</span></span>» (where <span class=\"tex-span\"><i>x</i></span>, <span class=\"tex-span\"><i>y</i></span> are integers, <span class=\"tex-span\">1 ≤ <i>x</i> ≤ <i>n</i></span>, <span class=\"tex-span\">1 ≤ <i>y</i> ≤ <i>m</i></span>, and <span class=\"tex-span\"><i>id</i></span> is a string of lower case Latin letters — from <span class=\"tex-span\">1</span> to <span class=\"tex-span\">10</span> characters long). That query means that the warehouse got a box identified as <span class=\"tex-span\"><i>id</i></span>, which should be put in the section <span class=\"tex-span\"><i>y</i></span> on the shelf <span class=\"tex-span\"><i>x</i></span>. If the section is full, use the rules described above. It is guaranteed that every moment of the process the identifiers of all the boxes in the warehouse are different. You don’t have to answer this query. </li><li> «<span class=\"tex-font-style-bf\"><span class=\"tex-font-style-tt\">-1 id</span></span>» (where <span class=\"tex-span\"><i>id</i></span> is a string of lower case Latin letters — from <span class=\"tex-span\">1</span> to <span class=\"tex-span\">10</span> characters long). That query means that a box identified as <span class=\"tex-span\"><i>id</i></span> is removed from the warehouse. You have to answer this query (see output format). </li></ul></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 30</span>, <span class=\"tex-span\">1 ≤ <i>k</i> ≤ 2000</span>) — the height, the width of shelving and the amount of the operations in the warehouse that you need to analyze. In the following <span class=\"tex-span\"><i>k</i></span> lines the queries are given in the order of appearance in the format described above.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>For each query of the «<span class=\"tex-font-style-bf\"><span class=\"tex-font-style-tt\">-1 id</span></span>» type output two numbers in a separate line — index of the shelf and index of the section where the box with this identifier lay. If there was no such box in the warehouse when the query was made, output «<span class=\"tex-font-style-bf\"><span class=\"tex-font-style-tt\">-1 -1</span></span>» without quotes.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 9<br/>+1 1 1 cola<br/>+1 1 1 fanta<br/>+1 1 1 sevenup<br/>+1 1 1 whitekey<br/>-1 cola<br/>-1 fanta<br/>-1 sevenup<br/>-1 whitekey<br/>-1 cola<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 1<br/>1 2<br/>2 1<br/>2 2<br/>-1 -1<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 8<br/>+1 1 1 cola<br/>-1 cola<br/>+1 1 1 fanta<br/>-1 fanta<br/>+1 1 1 sevenup<br/>-1 sevenup<br/>+1 1 1 whitekey<br/>-1 whitekey<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 1<br/>1 1<br/>1 1<br/>1 1<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"455df1a2d395d6ce21d0dd5f1d774a16\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"7003dee05763f371f54b8c55df1c6bd31fb72da1\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"B\" data-uuid=\"ps_8388b4bb37c5420f245dc0db272bd44b6c845115\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Warehouse</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Once upon a time, when the world was more beautiful, the sun shone brighter, the grass was greener and the sausages tasted better Arlandia was the most powerful country. And its capital was the place where our hero DravDe worked. He couldn’t program or make up problems (in fact, few people saw a computer those days) but he was nevertheless happy. He worked in a warehouse where a magical but non-alcoholic drink Ogudar-Olok was kept. We won’t describe his work in detail and take a better look at a simplified version of the warehouse.</p><p>The warehouse has one set of shelving. It has <span class=\"tex-span\"><i>n</i></span> shelves, each of which is divided into <span class=\"tex-span\"><i>m</i></span> sections. The shelves are numbered from top to bottom starting from <span class=\"tex-span\">1</span> and the sections of each shelf are numbered from left to right also starting from <span class=\"tex-span\">1</span>. Each section can contain exactly one box of the drink, and try as he might, DravDe can never put a box in a section that already has one. In the course of his work DravDe frequently notices that he has to put a box in a filled section. In that case his solution is simple. DravDe ignores that section and looks at the next one to the right. If it is empty, he puts the box there. Otherwise he keeps looking for the first empty section to the right. If no empty section is found by the end of the shelf, he looks at the shelf which is under it, then the next one, etc. Also each time he looks at a new shelf he starts from the shelf’s beginning. If DravDe still can’t find an empty section for the box, he immediately drinks it all up and throws the empty bottles away not to be caught.</p><p>After one great party with a lot of Ogudar-Olok drunk DravDe asked you to help him. Unlike him, you can program and therefore modeling the process of counting the boxes in the warehouse will be easy work for you.</p><p>The process of counting contains two types of query messages: </p><ul> <li> «<span class=\"tex-font-style-bf\"><span class=\"tex-font-style-tt\">+1 x y id</span></span>» (where <span class=\"tex-span\"><i>x</i></span>, <span class=\"tex-span\"><i>y</i></span> are integers, <span class=\"tex-span\">1 ≤ <i>x</i> ≤ <i>n</i></span>, <span class=\"tex-span\">1 ≤ <i>y</i> ≤ <i>m</i></span>, and <span class=\"tex-span\"><i>id</i></span> is a string of lower case Latin letters — from <span class=\"tex-span\">1</span> to <span class=\"tex-span\">10</span> characters long). That query means that the warehouse got a box identified as <span class=\"tex-span\"><i>id</i></span>, which should be put in the section <span class=\"tex-span\"><i>y</i></span> on the shelf <span class=\"tex-span\"><i>x</i></span>. If the section is full, use the rules described above. It is guaranteed that every moment of the process the identifiers of all the boxes in the warehouse are different. You don’t have to answer this query. </li><li> «<span class=\"tex-font-style-bf\"><span class=\"tex-font-style-tt\">-1 id</span></span>» (where <span class=\"tex-span\"><i>id</i></span> is a string of lower case Latin letters — from <span class=\"tex-span\">1</span> to <span class=\"tex-span\">10</span> characters long). That query means that a box identified as <span class=\"tex-span\"><i>id</i></span> is removed from the warehouse. You have to answer this query (see output format). </li></ul></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 30</span>, <span class=\"tex-span\">1 ≤ <i>k</i> ≤ 2000</span>) — the height, the width of shelving and the amount of the operations in the warehouse that you need to analyze. In the following <span class=\"tex-span\"><i>k</i></span> lines the queries are given in the order of appearance in the format described above.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>For each query of the «<span class=\"tex-font-style-bf\"><span class=\"tex-font-style-tt\">-1 id</span></span>» type output two numbers in a separate line — index of the shelf and index of the section where the box with this identifier lay. If there was no such box in the warehouse when the query was made, output «<span class=\"tex-font-style-bf\"><span class=\"tex-font-style-tt\">-1 -1</span></span>» without quotes.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 9<br />+1 1 1 cola<br />+1 1 1 fanta<br />+1 1 1 sevenup<br />+1 1 1 whitekey<br />-1 cola<br />-1 fanta<br />-1 sevenup<br />-1 whitekey<br />-1 cola<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 1<br />1 2<br />2 1<br />2 2<br />-1 -1<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 8<br />+1 1 1 cola<br />-1 cola<br />+1 1 1 fanta<br />-1 fanta<br />+1 1 1 sevenup<br />-1 sevenup<br />+1 1 1 whitekey<br />-1 whitekey<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 1<br />1 1<br />1 1<br />1 1<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=B]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if (result[\"success\"] === \"true\") {\r\n Codeforces.facebox(\".diff-popup\", \"//codeforces.org/s/73366\");\r\n 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{document.onreadystatechange = prev;handler();}};}})();</script></body>\n</html>\n"},"long_tags":{"kind":"string","value":"[\"Implementation problems, programming technics, simulation\"]"},"short_tags":{"kind":"string","value":"[\"implementation\", \"*1700\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":163,"cells":{"problem_id":{"kind":"string","value":"35C"},"contest":{"kind":"string","value":"35"},"problem":{"kind":"string","value":"C"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"C. Fire Again"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Fire Again</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>After a terrifying forest fire in Berland a forest rebirth program was carried out. Due to it <span class=\"tex-span\"><i>N</i></span> rows with <span class=\"tex-span\"><i>M</i></span> trees each were planted and the rows were so neat that one could map it on a system of coordinates so that the <span class=\"tex-span\"><i>j</i></span>-th tree in the <span class=\"tex-span\"><i>i</i></span>-th row would have the coordinates of <span class=\"tex-span\">(<i>i</i>, <i>j</i>)</span>. However a terrible thing happened and the young forest caught fire. Now we must find the coordinates of the tree that will catch fire last to plan evacuation.</p><p>The burning began in <span class=\"tex-span\"><i>K</i></span> points simultaneously, which means that initially <span class=\"tex-span\"><i>K</i></span> trees started to burn. Every minute the fire gets from the burning trees to the ones that aren’t burning and that the distance from them to the nearest burning tree equals to 1.</p><p>Find the tree that will be the last to start burning. If there are several such trees, output any.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains two integers <span class=\"tex-span\"><i>N</i>, <i>M</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i>, <i>M</i> ≤ 2000</span>) — the size of the forest. The trees were planted in all points of the (<span class=\"tex-span\"><i>x</i>, <i>y</i></span>) (<span class=\"tex-span\">1 ≤ <i>x</i> ≤ <i>N</i>, 1 ≤ <i>y</i> ≤ <i>M</i></span>) type, <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> are integers.</p><p>The second line contains an integer <span class=\"tex-span\"><i>K</i></span> (<span class=\"tex-span\">1 ≤ <i>K</i> ≤ 10</span>) — amount of trees, burning in the beginning. </p><p>The third line contains <span class=\"tex-span\"><i>K</i></span> pairs of integers: <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\">1</sub>, <i>y</i><sub class=\"lower-index\">1</sub>, <i>x</i><sub class=\"lower-index\">2</sub>, <i>y</i><sub class=\"lower-index\">2</sub>, ..., <i>x</i><sub class=\"lower-index\"><i>k</i></sub>, <i>y</i><sub class=\"lower-index\"><i>k</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>x</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>N</i>, 1 ≤ <i>y</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>M</i></span>) — coordinates of the points from which the fire started. It is guaranteed that no two points coincide.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a line with two space-separated integers <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> — coordinates of the tree that will be the last one to start burning. If there are several such trees, output any.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br/>1<br/>2 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 1<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br/>1<br/>1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3 3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br/>2<br/>1 1 3 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 2</pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"ba213a6e03040e4919c1bc183c3ae49d\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"7003dee05763f371f54b8c55df1c6bd31fb72da1\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"C\" data-uuid=\"ps_7cf60d263144fbfe79879103502132ec28aac689\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Fire Again</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>After a terrifying forest fire in Berland a forest rebirth program was carried out. Due to it <span class=\"tex-span\"><i>N</i></span> rows with <span class=\"tex-span\"><i>M</i></span> trees each were planted and the rows were so neat that one could map it on a system of coordinates so that the <span class=\"tex-span\"><i>j</i></span>-th tree in the <span class=\"tex-span\"><i>i</i></span>-th row would have the coordinates of <span class=\"tex-span\">(<i>i</i>, <i>j</i>)</span>. However a terrible thing happened and the young forest caught fire. Now we must find the coordinates of the tree that will catch fire last to plan evacuation.</p><p>The burning began in <span class=\"tex-span\"><i>K</i></span> points simultaneously, which means that initially <span class=\"tex-span\"><i>K</i></span> trees started to burn. Every minute the fire gets from the burning trees to the ones that aren’t burning and that the distance from them to the nearest burning tree equals to 1.</p><p>Find the tree that will be the last to start burning. If there are several such trees, output any.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains two integers <span class=\"tex-span\"><i>N</i>, <i>M</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i>, <i>M</i> ≤ 2000</span>) — the size of the forest. The trees were planted in all points of the (<span class=\"tex-span\"><i>x</i>, <i>y</i></span>) (<span class=\"tex-span\">1 ≤ <i>x</i> ≤ <i>N</i>, 1 ≤ <i>y</i> ≤ <i>M</i></span>) type, <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> are integers.</p><p>The second line contains an integer <span class=\"tex-span\"><i>K</i></span> (<span class=\"tex-span\">1 ≤ <i>K</i> ≤ 10</span>) — amount of trees, burning in the beginning. </p><p>The third line contains <span class=\"tex-span\"><i>K</i></span> pairs of integers: <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\">1</sub>, <i>y</i><sub class=\"lower-index\">1</sub>, <i>x</i><sub class=\"lower-index\">2</sub>, <i>y</i><sub class=\"lower-index\">2</sub>, ..., <i>x</i><sub class=\"lower-index\"><i>k</i></sub>, <i>y</i><sub class=\"lower-index\"><i>k</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>x</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>N</i>, 1 ≤ <i>y</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>M</i></span>) — coordinates of the points from which the fire started. It is guaranteed that no two points coincide.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a line with two space-separated integers <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> — coordinates of the tree that will be the last one to start burning. If there are several such trees, output any.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br />1<br />2 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 1<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br />1<br />1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3 3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br />2<br />1 1 3 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 2</pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let 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\"*1500\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":164,"cells":{"problem_id":{"kind":"string","value":"35D"},"contest":{"kind":"string","value":"35"},"problem":{"kind":"string","value":"D"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"D. Animals"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Animals</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Once upon a time DravDe, an outstanding person famous for his professional achievements (as you must remember, he works in a warehouse storing Ogudar-Olok, a magical but non-alcoholic drink) came home after a hard day. That day he had to drink 9875 boxes of the drink and, having come home, he went to bed at once.</p><p>DravDe dreamt about managing a successful farm. He dreamt that every day one animal came to him and asked him to let it settle there. However, DravDe, being unimaginably kind, could send the animal away and it went, rejected. There were exactly <span class=\"tex-span\"><i>n</i></span> days in DravDe’s dream and the animal that came on the <span class=\"tex-span\"><i>i</i></span>-th day, ate exactly <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> tons of food daily starting from day <span class=\"tex-span\"><i>i</i></span>. But if one day the animal could not get the food it needed, it got really sad. At the very beginning of the dream there were exactly <span class=\"tex-span\"><i>X</i></span> tons of food on the farm.</p><p>DravDe woke up terrified...</p><p>When he retold the dream to you, he couldn’t remember how many animals were on the farm by the end of the <span class=\"tex-span\"><i>n</i></span>-th day any more, but he did remember that nobody got sad (as it was a happy farm) and that there was the maximum possible amount of the animals. That’s the number he wants you to find out. </p><p>It should be noticed that the animals arrived in the morning and DravDe only started to feed them in the afternoon, so that if an animal willing to join them is rejected, it can’t eat any farm food. But if the animal does join the farm, it eats daily from that day to the <span class=\"tex-span\"><i>n</i></span>-th.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>X</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100, 1 ≤ <i>X</i> ≤ 10<sup class=\"upper-index\">4</sup></span>) — amount of days in DravDe’s dream and the total amount of food (in tons) that was there initially. The second line contains integers <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>c</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 300</span>). Numbers in the second line are divided by a space.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the only number — the maximum possible amount of animals on the farm by the end of the <span class=\"tex-span\"><i>n</i></span>-th day given that the food was enough for everybody.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 4<br/>1 1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 6<br/>1 1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br/></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>Note to the first example: DravDe leaves the second and the third animal on the farm. The second animal will eat one ton of food on the second day and one ton on the third day. The third animal will eat one ton of food on the third day.</p></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"5101bfdad72920c100b148c49218ec50\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"7003dee05763f371f54b8c55df1c6bd31fb72da1\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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'))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_837c1b8c88b5e5727b3d88edb05d5eb15eb6392c\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Animals</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Once upon a time DravDe, an outstanding person famous for his professional achievements (as you must remember, he works in a warehouse storing Ogudar-Olok, a magical but non-alcoholic drink) came home after a hard day. That day he had to drink 9875 boxes of the drink and, having come home, he went to bed at once.</p><p>DravDe dreamt about managing a successful farm. He dreamt that every day one animal came to him and asked him to let it settle there. However, DravDe, being unimaginably kind, could send the animal away and it went, rejected. There were exactly <span class=\"tex-span\"><i>n</i></span> days in DravDe’s dream and the animal that came on the <span class=\"tex-span\"><i>i</i></span>-th day, ate exactly <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> tons of food daily starting from day <span class=\"tex-span\"><i>i</i></span>. But if one day the animal could not get the food it needed, it got really sad. At the very beginning of the dream there were exactly <span class=\"tex-span\"><i>X</i></span> tons of food on the farm.</p><p>DravDe woke up terrified...</p><p>When he retold the dream to you, he couldn’t remember how many animals were on the farm by the end of the <span class=\"tex-span\"><i>n</i></span>-th day any more, but he did remember that nobody got sad (as it was a happy farm) and that there was the maximum possible amount of the animals. That’s the number he wants you to find out. </p><p>It should be noticed that the animals arrived in the morning and DravDe only started to feed them in the afternoon, so that if an animal willing to join them is rejected, it can’t eat any farm food. But if the animal does join the farm, it eats daily from that day to the <span class=\"tex-span\"><i>n</i></span>-th.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>X</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100, 1 ≤ <i>X</i> ≤ 10<sup class=\"upper-index\">4</sup></span>) — amount of days in DravDe’s dream and the total amount of food (in tons) that was there initially. The second line contains integers <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>c</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 300</span>). Numbers in the second line are divided by a space.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the only number — the maximum possible amount of animals on the farm by the end of the <span class=\"tex-span\"><i>n</i></span>-th day given that the food was enough for everybody.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 4<br />1 1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 6<br />1 1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br /></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>Note to the first example: DravDe leaves the second and the third animal on the farm. The second animal will eat one ton of food on the second day and one ton on the third day. The third animal will eat one ton of food on the third day.</p></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if (result[\"success\"] === \"true\") {\r\n 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{document.onreadystatechange = prev;handler();}};}})();</script></body>\n</html>\n"},"long_tags":{"kind":"string","value":"[\"Dynamic programming\", \"Greedy algorithms\"]"},"short_tags":{"kind":"string","value":"[\"dp\", \"greedy\", \"*1700\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":165,"cells":{"problem_id":{"kind":"string","value":"35E"},"contest":{"kind":"string","value":"35"},"problem":{"kind":"string","value":"E"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"E. Parade"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Parade</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>No Great Victory anniversary in Berland has ever passed without the war parade. This year is not an exception. That’s why the preparations are on in full strength. Tanks are building a line, artillery mounts are ready to fire, soldiers are marching on the main square... And the air forces general Mr. Generalov is in trouble again. This year a lot of sky-scrapers have been built which makes it difficult for the airplanes to fly above the city. It was decided that the planes should fly strictly from south to north. Moreover, there must be no sky scraper on a plane’s route, otherwise the anniversary will become a tragedy. The Ministry of Building gave the data on <span class=\"tex-span\"><i>n</i></span> sky scrapers (the rest of the buildings are rather small and will not be a problem to the planes). When looking at the city from south to north as a geometrical plane, the <span class=\"tex-span\"><i>i</i></span>-th building is a rectangle of height <span class=\"tex-span\"><i>h</i><sub class=\"lower-index\"><i>i</i></sub></span>. Its westernmost point has the x-coordinate of <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span> and the easternmost — of <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>. The terrain of the area is plain so that all the buildings stand on one level. Your task as the Ministry of Defence’s head programmer is to find an <span class=\"tex-font-style-it\">enveloping</span> polyline using the data on the sky-scrapers. The polyline’s properties are as follows:</p><ul> <li> If you look at the city from south to north as a plane, then any part of any building will be inside or on the boarder of the area that the polyline encloses together with the land surface. </li><li> The polyline starts and ends on the land level, i.e. at the height equal to 0. </li><li> The segments of the polyline are parallel to the coordinate axes, i.e. they can only be vertical or horizontal. </li><li> The polyline’s vertices should have integer coordinates. </li><li> If you look at the city from south to north the polyline (together with the land surface) must enclose the minimum possible area. </li><li> The polyline must have the smallest length among all the polylines, enclosing the minimum possible area with the land. </li><li> The consecutive segments of the polyline must be perpendicular. </li></ul><center> <img class=\"tex-graphics\" height=\"151px\" src=\"https://espresso.codeforces.com/4e39fc62775d3334b80dc307395dbdac20ce0a4e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" width=\"680px\"/> </center><center> Picture to the second sample test (the enveloping polyline is marked on the right). </center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100000</span>). Then follow <span class=\"tex-span\"><i>n</i></span> lines, each containing three integers <span class=\"tex-span\"><i>h</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>h</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup>, - 10<sup class=\"upper-index\">9</sup> ≤ <i>l</i><sub class=\"lower-index\"><i>i</i></sub> < <i>r</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output integer <span class=\"tex-span\"><i>m</i></span> — amount of vertices of the enveloping polyline. The next <span class=\"tex-span\"><i>m</i></span> lines should contain 2 integers each — the position and the height of the polyline’s vertex. Output the coordinates of each vertex in the order of traversing the polyline from west to east. Remember that the first and the last vertices of the polyline should have the height of 0.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/>3 0 2<br/>4 1 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6<br/>0 0<br/>0 3<br/>1 3<br/>1 4<br/>3 4<br/>3 0<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5<br/>3 -3 0<br/>2 -1 1<br/>4 2 4<br/>2 3 7<br/>3 6 8<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>14<br/>-3 0<br/>-3 3<br/>0 3<br/>0 2<br/>1 2<br/>1 0<br/>2 0<br/>2 4<br/>4 4<br/>4 2<br/>6 2<br/>6 3<br/>8 3<br/>8 0<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"6b3ca0226a43d3b13fdb8eb974d187bd\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"7003dee05763f371f54b8c55df1c6bd31fb72da1\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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class=\"header\"><div class=\"title\">E. Parade</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>No Great Victory anniversary in Berland has ever passed without the war parade. This year is not an exception. That’s why the preparations are on in full strength. Tanks are building a line, artillery mounts are ready to fire, soldiers are marching on the main square... And the air forces general Mr. Generalov is in trouble again. This year a lot of sky-scrapers have been built which makes it difficult for the airplanes to fly above the city. It was decided that the planes should fly strictly from south to north. Moreover, there must be no sky scraper on a plane’s route, otherwise the anniversary will become a tragedy. The Ministry of Building gave the data on <span class=\"tex-span\"><i>n</i></span> sky scrapers (the rest of the buildings are rather small and will not be a problem to the planes). When looking at the city from south to north as a geometrical plane, the <span class=\"tex-span\"><i>i</i></span>-th building is a rectangle of height <span class=\"tex-span\"><i>h</i><sub class=\"lower-index\"><i>i</i></sub></span>. Its westernmost point has the x-coordinate of <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span> and the easternmost — of <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>. The terrain of the area is plain so that all the buildings stand on one level. Your task as the Ministry of Defence’s head programmer is to find an <span class=\"tex-font-style-it\">enveloping</span> polyline using the data on the sky-scrapers. The polyline’s properties are as follows:</p><ul> <li> If you look at the city from south to north as a plane, then any part of any building will be inside or on the boarder of the area that the polyline encloses together with the land surface. </li><li> The polyline starts and ends on the land level, i.e. at the height equal to 0. </li><li> The segments of the polyline are parallel to the coordinate axes, i.e. they can only be vertical or horizontal. </li><li> The polyline’s vertices should have integer coordinates. </li><li> If you look at the city from south to north the polyline (together with the land surface) must enclose the minimum possible area. </li><li> The polyline must have the smallest length among all the polylines, enclosing the minimum possible area with the land. </li><li> The consecutive segments of the polyline must be perpendicular. </li></ul><center> <img class=\"tex-graphics\" height=\"151px\" src=\"https://espresso.codeforces.com/4e39fc62775d3334b80dc307395dbdac20ce0a4e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" width=\"680px\" /> </center><center> Picture to the second sample test (the enveloping polyline is marked on the right). </center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100000</span>). Then follow <span class=\"tex-span\"><i>n</i></span> lines, each containing three integers <span class=\"tex-span\"><i>h</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>h</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup>, - 10<sup class=\"upper-index\">9</sup> ≤ <i>l</i><sub class=\"lower-index\"><i>i</i></sub> < <i>r</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output integer <span class=\"tex-span\"><i>m</i></span> — amount of vertices of the enveloping polyline. The next <span class=\"tex-span\"><i>m</i></span> lines should contain 2 integers each — the position and the height of the polyline’s vertex. Output the coordinates of each vertex in the order of traversing the polyline from west to east. Remember that the first and the last vertices of the polyline should have the height of 0.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br />3 0 2<br />4 1 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6<br />0 0<br />0 3<br />1 3<br />1 4<br />3 4<br />3 0<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5<br />3 -3 0<br />2 -1 1<br />4 2 4<br />2 3 7<br />3 6 8<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>14<br />-3 0<br />-3 3<br />0 3<br />0 2<br />1 2<br />1 0<br />2 0<br />2 4<br />4 4<br />4 2<br />6 2<br />6 3<br />8 3<br />8 0<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=E]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let 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\"*2100\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":166,"cells":{"problem_id":{"kind":"string","value":"36A"},"contest":{"kind":"string","value":"36"},"problem":{"kind":"string","value":"A"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"A. Extra-terrestrial Intelligence"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Extra-terrestrial Intelligence</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Recently Vasya got interested in finding extra-terrestrial intelligence. He made a simple extra-terrestrial signals’ receiver and was keeping a record of the signals for <span class=\"tex-span\"><i>n</i></span> days in a row. Each of those <span class=\"tex-span\"><i>n</i></span> days Vasya wrote a 1 in his notebook if he had received a signal that day and a 0 if he hadn’t. Vasya thinks that he has found extra-terrestrial intelligence if there is a system in the way the signals has been received, i.e. if all the intervals between successive signals are equal. Otherwise, Vasya thinks that the signals were sent by some stupid aliens no one cares about. Help Vasya to deduce from the information given by the receiver if he has found extra-terrestrial intelligence or not.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">3 ≤ <i>n</i> ≤ 100</span>) — amount of days during which Vasya checked if there were any signals. The second line contains <span class=\"tex-span\"><i>n</i></span> characters 1 or 0 — the record Vasya kept each of those <span class=\"tex-span\"><i>n</i></span> days. It’s guaranteed that the given record sequence contains at least three 1s.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>If Vasya has found extra-terrestrial intelligence, output <span class=\"tex-font-style-tt\">YES</span>, otherwise output <span class=\"tex-font-style-tt\">NO</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>8<br/>00111000<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>7<br/>1001011<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>7<br/>1010100<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"f886fbd775c2efd4bb4a973c0b94efe2\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"4112886c03acba7754afa5b6cc7ab967fa145a65\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/769\" title=\"Codeforces Beta Round #36 (Problem D solution)\" target=\"_blank\">Tutorial #4</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"151:152\" resourceName=\"Tutorial #4\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/770\" title=\"Codeforces Beta Round #36 (Problem A Tutorial)\" target=\"_blank\">Tutorial #5</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"530:531\" resourceName=\"Tutorial #5\"\r\nresourceManual=\"true\" 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}\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_42957ec1b6877e57e2c931873082947ed58317bb\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Extra-terrestrial Intelligence</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Recently Vasya got interested in finding extra-terrestrial intelligence. He made a simple extra-terrestrial signals’ receiver and was keeping a record of the signals for <span class=\"tex-span\"><i>n</i></span> days in a row. Each of those <span class=\"tex-span\"><i>n</i></span> days Vasya wrote a 1 in his notebook if he had received a signal that day and a 0 if he hadn’t. Vasya thinks that he has found extra-terrestrial intelligence if there is a system in the way the signals has been received, i.e. if all the intervals between successive signals are equal. Otherwise, Vasya thinks that the signals were sent by some stupid aliens no one cares about. Help Vasya to deduce from the information given by the receiver if he has found extra-terrestrial intelligence or not.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">3 ≤ <i>n</i> ≤ 100</span>) — amount of days during which Vasya checked if there were any signals. The second line contains <span class=\"tex-span\"><i>n</i></span> characters 1 or 0 — the record Vasya kept each of those <span class=\"tex-span\"><i>n</i></span> days. It’s guaranteed that the given record sequence contains at least three 1s.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>If Vasya has found extra-terrestrial intelligence, output <span class=\"tex-font-style-tt\">YES</span>, otherwise output <span class=\"tex-font-style-tt\">NO</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>8<br />00111000<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>7<br />1001011<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>7<br />1010100<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:08</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='bff5795e736ba9c233174f60d8665e4c'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/119880\">It's Happening! Meta Hacker Cup 2023 Schedule</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/DaviddeGea1\" title=\"Expert DaviddeGea1\" class=\"rated-user user-blue\">DaviddeGea1</a> →\r\n <a href=\"/blog/entry/70917\">Number of ways of dividing an array into 2 parts such that sum of each part is > k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a> →\r\n <a href=\"/blog/entry/74245\">Questions and doubts regarding Aliens DP trick</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/cgy4ever\" title=\"International Grandmaster cgy4ever\" class=\"rated-user user-red\">cgy4ever</a> →\r\n <a href=\"/blog/entry/8192\">Codeforces Round #190 — Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/hocky\" title=\"Candidate Master hocky\" class=\"rated-user user-violet\">hocky</a> →\r\n <a href=\"/blog/entry/95323\">FBHC wuining uw Day? Incwease uw stacc size! (ㅅ´ ˘ `)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/liouzhou_101\" title=\"International Master liouzhou_101\" class=\"rated-user user-orange\">liouzhou_101</a> →\r\n <a href=\"/blog/entry/87598\">Editorial of Codeforces Round #700</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div 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class=\"rated-user user-blue\">ankancool</a> →\r\n <a href=\"/blog/entry/121136\">Invitation to AstroByte 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/GeZhiyuan\" title=\"Grandmaster GeZhiyuan\" class=\"rated-user user-red\">GeZhiyuan</a> →\r\n <a href=\"/blog/entry/120943\">Codeforces Round 901 (Div. 1, Div. 2) Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a> →\r\n <a href=\"/blog/entry/120772\">PSA: Increase your stack size before the Meta Hacker Cup, here's how</a>\r\n <img alt=\"New 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title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bn00b\" title=\"Newbie Bn00b\" class=\"rated-user user-gray\">Bn00b</a> →\r\n <a href=\"/blog/entry/98820\">[FEATURE REQUEST : ATCODER] TOPICS TAGS AND SORTING BY SOLVE COUNT</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a> →\r\n <a href=\"/blog/entry/121163\">AtCoder Regular Contest 166 Announcement</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/windva\" title=\"Grandmaster windva\" class=\"rated-user user-red\">windva</a> →\r\n <a href=\"/blog/entry/120644\">Codeforces Round 899 (Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Misa-Misa\" title=\"Expert Misa-Misa\" class=\"rated-user user-blue\">Misa-Misa</a> →\r\n <a href=\"/blog/entry/121157\">Someone please help me understand this.</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/shivam565\" title=\"Specialist shivam565\" class=\"rated-user user-cyan\">shivam565</a> →\r\n <a href=\"/blog/entry/108348\">Total number of subarrays with sum atmost k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n </ul>\r\n </div>\r\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/recent-actions\">Detailed →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n</div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li><a\r\n href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"773\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/773\"> Codeforces Beta Round #36 (Problem E solution)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/20/2010 20:10\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">The problem is to divide edges of a graph into two groups forming two paths in the graph. Clearly, each path is contained in one connected component. So if the given graph has more than two connected components, the problem has no solution. The same we can say if the graph has more than four vertices of an odd degree. Indeed, each vertex in a path (even if the path contains some vertices more than once) have an even degree, exept the first vertex and the last vertex. So the union of two paths can contain no more than four odd vertices.<div><br /></div><div>Now consider the cases:</div><div><br /></div><div>1. One connected component, no vertices of an odd degree. So we have an euler cycle, which can be divided into two paths.</div><div><br /></div><div>2. One connected component, two odd vertices. The same with an euler path instead of euler cycle. There is a tricky case of a graph with only one edge, which cannot be divided into two nonempty paths.</div><div><br /></div><div>3. One connected component, four odd vertices. The most interesting case. Connect two vertices of an odd degree by a dummy edge. You will get a graph with an euler path. Find the euler path and delete the dummy edge - you will get two paths.</div><div><br /></div><div>4. Two connetced components, each having zero or two odd vertices. Two euler paths/cycles.</div><div><br /></div><div>5. Two connected components, four odd vertices in one and no odd vertices in another. No solution.</div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/36\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 36</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-773\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"773\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2336\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #36</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-773\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:gray'>0</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-773\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/20/2010 20:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/773#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/773#comments\">\n 0\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments 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Fractal"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Fractal</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Ever since Kalevitch, a famous Berland abstractionist, heard of fractals, he made them the main topic of his canvases. Every morning the artist takes a piece of graph paper and starts with making a model of his future canvas. He takes a square as big as <span class=\"tex-span\"><i>n</i> × <i>n</i></span> squares and paints some of them black. Then he takes a clean square piece of paper and paints the fractal using the following algorithm: </p><p>Step 1. The paper is divided into <span class=\"tex-span\"><i>n</i><sup class=\"upper-index\">2</sup></span> identical squares and some of them are painted black according to the model.</p><p>Step 2. Every square that remains white is divided into <span class=\"tex-span\"><i>n</i><sup class=\"upper-index\">2</sup></span> smaller squares and some of them are painted black according to the model.</p><p>Every following step repeats step 2.</p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/f55fec8483a8140526ea740b876c0ef5ee004e60.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/> </center><p>Unfortunately, this tiresome work demands too much time from the painting genius. Kalevitch has been dreaming of making the process automatic to move to making 3D or even 4D fractals.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">2 ≤ <i>n</i> ≤ 3</span>, <span class=\"tex-span\">1 ≤ <i>k</i> ≤ 5</span>), where <span class=\"tex-span\"><i>k</i></span> is the amount of steps of the algorithm. Each of the following <span class=\"tex-span\"><i>n</i></span> lines contains <span class=\"tex-span\"><i>n</i></span> symbols that determine the model. Symbol «.» stands for a white square, whereas «*» stands for a black one. It is guaranteed that the model has at least one white square. </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a matrix <span class=\"tex-span\"><i>n</i><sup class=\"upper-index\"><i>k</i></sup> × <i>n</i><sup class=\"upper-index\"><i>k</i></sup></span> which is what a picture should look like after <span class=\"tex-span\"><i>k</i></span> steps of the algorithm.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 3<br/>.*<br/>..<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>.*******<br/>..******<br/>.*.*****<br/>....****<br/>.***.***<br/>..**..**<br/>.*.*.*.*<br/>........<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 2<br/>.*.<br/>***<br/>.*.<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>.*.***.*.<br/>*********<br/>.*.***.*.<br/>*********<br/>*********<br/>*********<br/>.*.***.*.<br/>*********<br/>.*.***.*.<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"b0133d446da8f6784979ac257ee11391\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"4112886c03acba7754afa5b6cc7ab967fa145a65\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/36\">Codeforces Beta Round 36</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/36/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1600\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='b0133d446da8f6784979ac257ee11391'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"170\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='b0133d446da8f6784979ac257ee11391'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"170\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/764\" title=\"Codeforces Beta Round #35 (Div. 2) and Codeforces Beta Round #36\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"147:148\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/773\" title=\"Codeforces Beta Round #36 (Problem E solution)\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"154:155\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/774\" title=\"Codeforces Beta Round #36 (Problem C Tutorial)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(en)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"765\" resourceName=\"Codeforces Beta Round #36 (Problem C Tutorial)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/768\" title=\"Codeforces Beta Round #36 (Problem B solution)\" target=\"_blank\">Tutorial #3</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"149:150\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/769\" title=\"Codeforces Beta Round #36 (Problem D solution)\" target=\"_blank\">Tutorial #4</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"151:152\" resourceName=\"Tutorial #4\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/770\" title=\"Codeforces Beta Round #36 (Problem A Tutorial)\" target=\"_blank\">Tutorial #5</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"530:531\" resourceName=\"Tutorial #5\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/771\" title=\"Codeforces Beta Round #36\" target=\"_blank\">Tutorial #6 <span class=\"resource-locale\">(en)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"153\" resourceName=\"Codeforces Beta Round #36\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/36\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/36/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/36/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/36/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/36/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/36/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/36/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/36/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n 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}\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"B\" data-uuid=\"ps_f21901bddf7e0ff9b1da020a35d6d01cdfe78b5a\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Fractal</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Ever since Kalevitch, a famous Berland abstractionist, heard of fractals, he made them the main topic of his canvases. Every morning the artist takes a piece of graph paper and starts with making a model of his future canvas. He takes a square as big as <span class=\"tex-span\"><i>n</i> × <i>n</i></span> squares and paints some of them black. Then he takes a clean square piece of paper and paints the fractal using the following algorithm: </p><p>Step 1. The paper is divided into <span class=\"tex-span\"><i>n</i><sup class=\"upper-index\">2</sup></span> identical squares and some of them are painted black according to the model.</p><p>Step 2. Every square that remains white is divided into <span class=\"tex-span\"><i>n</i><sup class=\"upper-index\">2</sup></span> smaller squares and some of them are painted black according to the model.</p><p>Every following step repeats step 2.</p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/f55fec8483a8140526ea740b876c0ef5ee004e60.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> </center><p>Unfortunately, this tiresome work demands too much time from the painting genius. Kalevitch has been dreaming of making the process automatic to move to making 3D or even 4D fractals.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">2 ≤ <i>n</i> ≤ 3</span>, <span class=\"tex-span\">1 ≤ <i>k</i> ≤ 5</span>), where <span class=\"tex-span\"><i>k</i></span> is the amount of steps of the algorithm. Each of the following <span class=\"tex-span\"><i>n</i></span> lines contains <span class=\"tex-span\"><i>n</i></span> symbols that determine the model. Symbol «.» stands for a white square, whereas «*» stands for a black one. It is guaranteed that the model has at least one white square. </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a matrix <span class=\"tex-span\"><i>n</i><sup class=\"upper-index\"><i>k</i></sup> × <i>n</i><sup class=\"upper-index\"><i>k</i></sup></span> which is what a picture should look like after <span class=\"tex-span\"><i>k</i></span> steps of the algorithm.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 3<br />.*<br />..<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>.*******<br />..******<br />.*.*****<br />....****<br />.***.***<br />..**..**<br />.*.*.*.*<br />........<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 2<br />.*.<br />***<br />.*.<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>.*.***.*.<br />*********<br />.*.***.*.<br />*********<br />*********<br />*********<br />.*.***.*.<br />*********<br />.*.***.*.<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=B]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"773\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/773\"> Codeforces Beta Round #36 (Problem E solution)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/20/2010 20:10\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">The problem is to divide edges of a graph into two groups forming two paths in the graph. Clearly, each path is contained in one connected component. So if the given graph has more than two connected components, the problem has no solution. The same we can say if the graph has more than four vertices of an odd degree. Indeed, each vertex in a path (even if the path contains some vertices more than once) have an even degree, exept the first vertex and the last vertex. So the union of two paths can contain no more than four odd vertices.<div><br /></div><div>Now consider the cases:</div><div><br /></div><div>1. One connected component, no vertices of an odd degree. So we have an euler cycle, which can be divided into two paths.</div><div><br /></div><div>2. One connected component, two odd vertices. The same with an euler path instead of euler cycle. There is a tricky case of a graph with only one edge, which cannot be divided into two nonempty paths.</div><div><br /></div><div>3. One connected component, four odd vertices. The most interesting case. Connect two vertices of an odd degree by a dummy edge. You will get a graph with an euler path. Find the euler path and delete the dummy edge - you will get two paths.</div><div><br /></div><div>4. Two connetced components, each having zero or two odd vertices. Two euler paths/cycles.</div><div><br /></div><div>5. Two connected components, four odd vertices in one and no odd vertices in another. No solution.</div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/36\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 36</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-773\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"773\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", 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src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:gray'>0</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-773\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/20/2010 20:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/773#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/773#comments\">\n 0\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments 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Bowls"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Bowls</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Once Petya was in such a good mood that he decided to help his mum with the washing-up. There were <span class=\"tex-span\"><i>n</i></span> dirty bowls in the sink. From the geometrical point of view each bowl looks like a blunted cone. We can disregard the width of the walls and bottom. Petya puts the clean bowls one on another naturally, i. e. so that their vertical axes coincide (see the picture). You will be given the order in which Petya washes the bowls. Determine the height of the construction, i.e. the distance from the bottom of the lowest bowl to the top of the highest one. </p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/ade4ca2e5b2b3327efb038896a20fd4868a08702.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/> </center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 3000</span>). Each of the following <span class=\"tex-span\"><i>n</i></span> lines contains 3 integers <span class=\"tex-span\"><i>h</i></span>, <span class=\"tex-span\"><i>r</i></span> and <span class=\"tex-span\"><i>R</i></span> (<span class=\"tex-span\">1 ≤ <i>h</i> ≤ 10000, 1 ≤ <i>r</i> < <i>R</i> ≤ 10000</span>). They are the height of a bowl, the radius of its bottom and the radius of its top. The plates are given in the order Petya puts them on the table.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the height of the plate pile accurate to at least <span class=\"tex-span\">10<sup class=\"upper-index\"> - 6</sup></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/>40 10 50<br/>60 20 30<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>70.00000000<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>50 30 80<br/>35 25 70<br/>40 10 90<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>55.00000000<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"2b1564ccec195f8d998d2dc7b465aad0\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"4112886c03acba7754afa5b6cc7ab967fa145a65\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/36\">Codeforces Beta Round 36</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='2b1564ccec195f8d998d2dc7b465aad0'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/36/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Geometry, computational geometry\">\r\n geometry\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2200\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='2b1564ccec195f8d998d2dc7b465aad0'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"171\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='2b1564ccec195f8d998d2dc7b465aad0'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"171\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/764\" title=\"Codeforces Beta Round #35 (Div. 2) and Codeforces Beta Round #36\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"147:148\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/773\" title=\"Codeforces Beta Round #36 (Problem E solution)\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"154:155\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/774\" title=\"Codeforces Beta Round #36 (Problem C Tutorial)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(en)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"765\" resourceName=\"Codeforces Beta Round #36 (Problem C Tutorial)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/768\" title=\"Codeforces Beta Round #36 (Problem B solution)\" 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pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Bowls</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Once Petya was in such a good mood that he decided to help his mum with the washing-up. There were <span class=\"tex-span\"><i>n</i></span> dirty bowls in the sink. From the geometrical point of view each bowl looks like a blunted cone. We can disregard the width of the walls and bottom. Petya puts the clean bowls one on another naturally, i. e. so that their vertical axes coincide (see the picture). You will be given the order in which Petya washes the bowls. Determine the height of the construction, i.e. the distance from the bottom of the lowest bowl to the top of the highest one. </p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/ade4ca2e5b2b3327efb038896a20fd4868a08702.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> </center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 3000</span>). Each of the following <span class=\"tex-span\"><i>n</i></span> lines contains 3 integers <span class=\"tex-span\"><i>h</i></span>, <span class=\"tex-span\"><i>r</i></span> and <span class=\"tex-span\"><i>R</i></span> (<span class=\"tex-span\">1 ≤ <i>h</i> ≤ 10000, 1 ≤ <i>r</i> < <i>R</i> ≤ 10000</span>). They are the height of a bowl, the radius of its bottom and the radius of its top. The plates are given in the order Petya puts them on the table.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the height of the plate pile accurate to at least <span class=\"tex-span\">10<sup class=\"upper-index\"> - 6</sup></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br />40 10 50<br />60 20 30<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>70.00000000<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />50 30 80<br />35 25 70<br />40 10 90<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>55.00000000<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let uuid = 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='bff5795e736ba9c233174f60d8665e4c'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/20/2010 20:10\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">The problem is to divide edges of a graph into two groups forming two paths in the graph. Clearly, each path is contained in one connected component. So if the given graph has more than two connected components, the problem has no solution. The same we can say if the graph has more than four vertices of an odd degree. Indeed, each vertex in a path (even if the path contains some vertices more than once) have an even degree, exept the first vertex and the last vertex. So the union of two paths can contain no more than four odd vertices.<div><br /></div><div>Now consider the cases:</div><div><br /></div><div>1. One connected component, no vertices of an odd degree. So we have an euler cycle, which can be divided into two paths.</div><div><br /></div><div>2. One connected component, two odd vertices. The same with an euler path instead of euler cycle. There is a tricky case of a graph with only one edge, which cannot be divided into two nonempty paths.</div><div><br /></div><div>3. One connected component, four odd vertices. The most interesting case. Connect two vertices of an odd degree by a dummy edge. You will get a graph with an euler path. Find the euler path and delete the dummy edge - you will get two paths.</div><div><br /></div><div>4. Two connetced components, each having zero or two odd vertices. Two euler paths/cycles.</div><div><br /></div><div>5. Two connected components, four odd vertices in one and no odd vertices in another. 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New Game with a Chess Piece"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. New Game with a Chess Piece</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Petya and Vasya are inventing a new game that requires a rectangular board and one chess piece. At the beginning of the game the piece stands in the upper-left corner of the board. Two players move the piece in turns. Each turn the chess piece can be moved either one square to the right or one square down or jump <span class=\"tex-span\"><i>k</i></span> squares diagonally down and to the right. The player who can’t move the piece loses. </p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/2519f63e583e64b29cde30065142915b2679da0b.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/> </center><p>The guys haven’t yet thought what to call the game or the best size of the board for it. Your task is to write a program that can determine the outcome of the game depending on the board size.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains two integers <span class=\"tex-span\"><i>t</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>t</i> ≤ 20</span>, <span class=\"tex-span\">1 ≤ <i>k</i> ≤ 10<sup class=\"upper-index\">9</sup></span>). Each of the following <span class=\"tex-span\"><i>t</i></span> lines contains two numbers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> — the board’s length and width (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 10<sup class=\"upper-index\">9</sup></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output <span class=\"tex-span\"><i>t</i></span> lines that can determine the outcomes of the game on every board. Write «+» if the first player is a winner, and «-» otherwise.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>10 2<br/>1 1<br/>1 2<br/>2 1<br/>2 2<br/>1 3<br/>2 3<br/>3 1<br/>3 2<br/>3 3<br/>4 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>-<br/>+<br/>+<br/>-<br/>-<br/>+<br/>-<br/>+<br/>+<br/>+<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"48b4490ce32b1e26ef6d823e725aba64\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"4112886c03acba7754afa5b6cc7ab967fa145a65\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/36\">Codeforces Beta Round 36</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/36/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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title=\"Codeforces Beta Round #35 (Div. 2) and Codeforces Beta Round #36\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"147:148\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/773\" title=\"Codeforces Beta Round #36 (Problem E solution)\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"154:155\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/774\" title=\"Codeforces Beta Round #36 (Problem C Tutorial)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(en)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"765\" resourceName=\"Codeforces Beta Round #36 (Problem C Tutorial)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/768\" title=\"Codeforces Beta Round #36 (Problem B solution)\" target=\"_blank\">Tutorial #3</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"149:150\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/769\" title=\"Codeforces Beta Round #36 (Problem D solution)\" target=\"_blank\">Tutorial #4</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"151:152\" resourceName=\"Tutorial #4\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/770\" title=\"Codeforces Beta Round #36 (Problem A Tutorial)\" target=\"_blank\">Tutorial #5</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"530:531\" resourceName=\"Tutorial #5\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/771\" title=\"Codeforces Beta Round #36\" target=\"_blank\">Tutorial #6 <span class=\"resource-locale\">(en)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"153\" resourceName=\"Codeforces Beta Round #36\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/36\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/36/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/36/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/36/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/36/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/36/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/36/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/36/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_8ea25381b4854d7ba15590af8f8a253b1856e540\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. New Game with a Chess Piece</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Petya and Vasya are inventing a new game that requires a rectangular board and one chess piece. At the beginning of the game the piece stands in the upper-left corner of the board. Two players move the piece in turns. Each turn the chess piece can be moved either one square to the right or one square down or jump <span class=\"tex-span\"><i>k</i></span> squares diagonally down and to the right. The player who can’t move the piece loses. </p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/2519f63e583e64b29cde30065142915b2679da0b.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> </center><p>The guys haven’t yet thought what to call the game or the best size of the board for it. Your task is to write a program that can determine the outcome of the game depending on the board size.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains two integers <span class=\"tex-span\"><i>t</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>t</i> ≤ 20</span>, <span class=\"tex-span\">1 ≤ <i>k</i> ≤ 10<sup class=\"upper-index\">9</sup></span>). Each of the following <span class=\"tex-span\"><i>t</i></span> lines contains two numbers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> — the board’s length and width (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 10<sup class=\"upper-index\">9</sup></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output <span class=\"tex-span\"><i>t</i></span> lines that can determine the outcomes of the game on every board. Write «+» if the first player is a winner, and «-» otherwise.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>10 2<br />1 1<br />1 2<br />2 1<br />2 2<br />1 3<br />2 3<br />3 1<br />3 2<br />3 3<br />4 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>-<br />+<br />+<br />-<br />-<br />+<br />-<br />+<br />+<br />+<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:08</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='bff5795e736ba9c233174f60d8665e4c'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/119880\">It's Happening! Meta Hacker Cup 2023 Schedule</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/DaviddeGea1\" title=\"Expert DaviddeGea1\" class=\"rated-user user-blue\">DaviddeGea1</a> →\r\n <a href=\"/blog/entry/70917\">Number of ways of dividing an array into 2 parts such that sum of each part is > k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a> →\r\n <a href=\"/blog/entry/74245\">Questions and doubts regarding Aliens DP trick</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/cgy4ever\" title=\"International Grandmaster cgy4ever\" class=\"rated-user user-red\">cgy4ever</a> →\r\n <a href=\"/blog/entry/8192\">Codeforces Round #190 — Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/hocky\" title=\"Candidate Master hocky\" class=\"rated-user user-violet\">hocky</a> →\r\n <a href=\"/blog/entry/95323\">FBHC wuining uw Day? Incwease uw stacc size! (ㅅ´ ˘ `)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/liouzhou_101\" title=\"International Master liouzhou_101\" class=\"rated-user user-orange\">liouzhou_101</a> →\r\n <a href=\"/blog/entry/87598\">Editorial of Codeforces Round #700</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div 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class=\"rated-user user-blue\">ankancool</a> →\r\n <a href=\"/blog/entry/121136\">Invitation to AstroByte 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/GeZhiyuan\" title=\"Grandmaster GeZhiyuan\" class=\"rated-user user-red\">GeZhiyuan</a> →\r\n <a href=\"/blog/entry/120943\">Codeforces Round 901 (Div. 1, Div. 2) Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a> →\r\n <a href=\"/blog/entry/120772\">PSA: Increase your stack size before the Meta Hacker Cup, here's how</a>\r\n <img alt=\"New 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title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bn00b\" title=\"Newbie Bn00b\" class=\"rated-user user-gray\">Bn00b</a> →\r\n <a href=\"/blog/entry/98820\">[FEATURE REQUEST : ATCODER] TOPICS TAGS AND SORTING BY SOLVE COUNT</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a> →\r\n <a href=\"/blog/entry/121163\">AtCoder Regular Contest 166 Announcement</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/windva\" title=\"Grandmaster windva\" class=\"rated-user user-red\">windva</a> →\r\n <a href=\"/blog/entry/120644\">Codeforces Round 899 (Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Misa-Misa\" title=\"Expert Misa-Misa\" class=\"rated-user user-blue\">Misa-Misa</a> →\r\n <a href=\"/blog/entry/121157\">Someone please help me understand this.</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/shivam565\" title=\"Specialist shivam565\" class=\"rated-user user-cyan\">shivam565</a> →\r\n <a href=\"/blog/entry/108348\">Total number of subarrays with sum atmost k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n </ul>\r\n </div>\r\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/recent-actions\">Detailed →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n</div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li><a\r\n href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"773\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/773\"> Codeforces Beta Round #36 (Problem E solution)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/20/2010 20:10\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">The problem is to divide edges of a graph into two groups forming two paths in the graph. Clearly, each path is contained in one connected component. So if the given graph has more than two connected components, the problem has no solution. The same we can say if the graph has more than four vertices of an odd degree. Indeed, each vertex in a path (even if the path contains some vertices more than once) have an even degree, exept the first vertex and the last vertex. So the union of two paths can contain no more than four odd vertices.<div><br /></div><div>Now consider the cases:</div><div><br /></div><div>1. One connected component, no vertices of an odd degree. So we have an euler cycle, which can be divided into two paths.</div><div><br /></div><div>2. One connected component, two odd vertices. The same with an euler path instead of euler cycle. There is a tricky case of a graph with only one edge, which cannot be divided into two nonempty paths.</div><div><br /></div><div>3. One connected component, four odd vertices. The most interesting case. Connect two vertices of an odd degree by a dummy edge. You will get a graph with an euler path. Find the euler path and delete the dummy edge - you will get two paths.</div><div><br /></div><div>4. Two connetced components, each having zero or two odd vertices. Two euler paths/cycles.</div><div><br /></div><div>5. Two connected components, four odd vertices in one and no odd vertices in another. No solution.</div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/36\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 36</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-773\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"773\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2336\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #36</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-773\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:gray'>0</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-773\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/20/2010 20:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/773#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/773#comments\">\n 0\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments 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Two Paths"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Two Paths</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Once archaeologists found <span class=\"tex-span\"><i>m</i></span> mysterious papers, each of which had a pair of integers written on them. Ancient people were known to like writing down the indexes of the roads they walked along, as «<span class=\"tex-span\"><i>a</i></span> <span class=\"tex-span\"><i>b</i></span>» or «<span class=\"tex-span\"><i>b</i></span> <span class=\"tex-span\"><i>a</i></span>», where <span class=\"tex-span\"><i>a</i>, <i>b</i></span> are the indexes of two different cities joint by the road . It is also known that the mysterious papers are pages of two travel journals (those days a new journal was written for every new journey).</p><p>During one journey the traveler could walk along one and the same road several times in one or several directions but in that case he wrote a new entry for each time in his journal. Besides, the archaeologists think that the direction the traveler took on a road had no effect upon the entry: the entry that looks like «<span class=\"tex-span\"><i>a</i></span> <span class=\"tex-span\"><i>b</i></span>» could refer to the road from <span class=\"tex-span\"><i>a</i></span> to <span class=\"tex-span\"><i>b</i></span> as well as to the road from <span class=\"tex-span\"><i>b</i></span> to <span class=\"tex-span\"><i>a</i></span>.</p><p>The archaeologists want to put the pages in the right order and reconstruct the two travel paths but unfortunately, they are bad at programming. That’s where you come in. Go help them!</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integer <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">1 ≤ <i>m</i> ≤ 10000</span>). Each of the following <span class=\"tex-span\"><i>m</i></span> lines describes one paper. Each description consists of two integers <span class=\"tex-span\"><i>a</i>, <i>b</i></span> (<span class=\"tex-span\">1 ≤ <i>a</i>, <i>b</i> ≤ 10000</span>, <span class=\"tex-span\"><i>a</i> ≠ <i>b</i></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the number <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">1</sub></span>. That is the length of the first path, i.e. the amount of papers in its description. In the following line output <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">1</sub></span> space-separated numbers — the indexes of the papers that describe the first path. In the third and fourth lines output similarly the length of the second path <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">2</sub></span> and the path itself. Both paths must contain at least one road, i.e. condition <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">1</sub> > 0</span> and <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">2</sub> > 0</span> must be met. The papers are numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>m</i></span> according to the order of their appearance in the input file. The numbers should be output in the order in which the traveler passed the corresponding roads. If the answer is not unique, output any.</p><p>If it’s impossible to find such two paths, output «<span class=\"tex-font-style-tt\">-1</span>».</p><p>Don’t forget that each paper should be used exactly once, i.e <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">1</sub> + <i>L</i><sub class=\"lower-index\">2</sub> = <i>m</i></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/>4 5<br/>4 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/>2 <br/>1<br/>1<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1<br/>1 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>-1<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"8cd8617b08a2b19cc1e01ffcdbca0795\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"4112886c03acba7754afa5b6cc7ab967fa145a65\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/36\">Codeforces Beta Round 36</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/36/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Constructive algorithms\">\r\n constructive algorithms\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Disjoint set union\">\r\n dsu\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Graphs\">\r\n graphs\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2600\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='8cd8617b08a2b19cc1e01ffcdbca0795'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"173\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' 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$(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/764\" title=\"Codeforces Beta Round #35 (Div. 2) and Codeforces Beta Round #36\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"147:148\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/773\" title=\"Codeforces Beta Round #36 (Problem E solution)\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"154:155\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/774\" title=\"Codeforces Beta Round #36 (Problem C Tutorial)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(en)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"765\" resourceName=\"Codeforces Beta Round #36 (Problem C Tutorial)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/768\" title=\"Codeforces Beta Round #36 (Problem B solution)\" target=\"_blank\">Tutorial #3</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"149:150\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/769\" title=\"Codeforces Beta Round #36 (Problem D solution)\" target=\"_blank\">Tutorial #4</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"151:152\" resourceName=\"Tutorial #4\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/770\" title=\"Codeforces Beta Round #36 (Problem A Tutorial)\" target=\"_blank\">Tutorial #5</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"530:531\" resourceName=\"Tutorial #5\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/771\" title=\"Codeforces Beta Round #36\" target=\"_blank\">Tutorial #6 <span class=\"resource-locale\">(en)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"153\" resourceName=\"Codeforces Beta Round #36\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/36\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/36/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/36/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/36/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/36/hacks\">Hacks</a></li>\r\n <li><a\r\n 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node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"E\" data-uuid=\"ps_fc5963f91ecb633151b30fdf6ff20aa54655b6ab\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Two Paths</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>input.txt</div><div class=\"output-file\"><div class=\"property-title\">output</div>output.txt</div></div><div><p>Once archaeologists found <span class=\"tex-span\"><i>m</i></span> mysterious papers, each of which had a pair of integers written on them. Ancient people were known to like writing down the indexes of the roads they walked along, as «<span class=\"tex-span\"><i>a</i></span> <span class=\"tex-span\"><i>b</i></span>» or «<span class=\"tex-span\"><i>b</i></span> <span class=\"tex-span\"><i>a</i></span>», where <span class=\"tex-span\"><i>a</i>, <i>b</i></span> are the indexes of two different cities joint by the road . It is also known that the mysterious papers are pages of two travel journals (those days a new journal was written for every new journey).</p><p>During one journey the traveler could walk along one and the same road several times in one or several directions but in that case he wrote a new entry for each time in his journal. Besides, the archaeologists think that the direction the traveler took on a road had no effect upon the entry: the entry that looks like «<span class=\"tex-span\"><i>a</i></span> <span class=\"tex-span\"><i>b</i></span>» could refer to the road from <span class=\"tex-span\"><i>a</i></span> to <span class=\"tex-span\"><i>b</i></span> as well as to the road from <span class=\"tex-span\"><i>b</i></span> to <span class=\"tex-span\"><i>a</i></span>.</p><p>The archaeologists want to put the pages in the right order and reconstruct the two travel paths but unfortunately, they are bad at programming. That’s where you come in. Go help them!</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains integer <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">1 ≤ <i>m</i> ≤ 10000</span>). Each of the following <span class=\"tex-span\"><i>m</i></span> lines describes one paper. Each description consists of two integers <span class=\"tex-span\"><i>a</i>, <i>b</i></span> (<span class=\"tex-span\">1 ≤ <i>a</i>, <i>b</i> ≤ 10000</span>, <span class=\"tex-span\"><i>a</i> ≠ <i>b</i></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the number <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">1</sub></span>. That is the length of the first path, i.e. the amount of papers in its description. In the following line output <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">1</sub></span> space-separated numbers — the indexes of the papers that describe the first path. In the third and fourth lines output similarly the length of the second path <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">2</sub></span> and the path itself. Both paths must contain at least one road, i.e. condition <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">1</sub> > 0</span> and <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">2</sub> > 0</span> must be met. The papers are numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>m</i></span> according to the order of their appearance in the input file. The numbers should be output in the order in which the traveler passed the corresponding roads. If the answer is not unique, output any.</p><p>If it’s impossible to find such two paths, output «<span class=\"tex-font-style-tt\">-1</span>».</p><p>Don’t forget that each paper should be used exactly once, i.e <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\">1</sub> + <i>L</i><sub class=\"lower-index\">2</sub> = <i>m</i></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br />4 5<br />4 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br />2 <br />1<br />1<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1<br />1 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>-1<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=E]\");\r\n let uuid = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='bff5795e736ba9c233174f60d8665e4c'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n </label>\r\n </div>\r\n <div style=\"padding: 0 1em 1em 1em;text-align:right;\">\r\n <input style=\"height:1.65em;padding:0 0.75em;\" type=\"submit\" value=\"Find\"/>\r\n </div>\r\n </form>\r\n </div>\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".handleBox\").autocomplete(\"/data/handles\", {\r\n delay: 200,\r\n width: 200,\r\n selectFirst: false,\r\n matchContains: true,\r\n minChars: 3\r\n });\r\n $(\".handleForm\").attr(\"autocomplete\", \"off\").submit(function () {\r\n var link = \"/profile/userHandle\".replace(\r\n \"userHandle\", $(this).find(\".handleBox\").val()\r\n );\r\n window.location = link;\r\n return false;\r\n });\r\n });\n </script>\n\r\n\r\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Recent actions\n <div class=\"top-links\">\n </div>\n </div>\n <div class=\"recent-actions\">\r\n <ul>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a href=\"/blog/entry/121171\">An Interesting Tree Problem</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/.Danet\" title=\"Expert .Danet\" class=\"rated-user user-blue\">.Danet</a> →\r\n <a href=\"/blog/entry/121172\">[TLE on pretest1]</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/sszcdjr\" title=\"Master sszcdjr\" class=\"rated-user user-orange\">sszcdjr</a> →\r\n <a href=\"/blog/entry/119859\">Codeforces Round 896 (Div. 1, Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/119880\">It's Happening! Meta Hacker Cup 2023 Schedule</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/DaviddeGea1\" title=\"Expert DaviddeGea1\" class=\"rated-user user-blue\">DaviddeGea1</a> →\r\n <a href=\"/blog/entry/70917\">Number of ways of dividing an array into 2 parts such that sum of each part is > k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a> →\r\n <a href=\"/blog/entry/74245\">Questions and doubts regarding Aliens DP trick</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/cgy4ever\" title=\"International Grandmaster cgy4ever\" class=\"rated-user user-red\">cgy4ever</a> →\r\n <a href=\"/blog/entry/8192\">Codeforces Round #190 — Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/hocky\" title=\"Candidate Master hocky\" class=\"rated-user user-violet\">hocky</a> →\r\n <a href=\"/blog/entry/95323\">FBHC wuining uw Day? Incwease uw stacc size! (ㅅ´ ˘ `)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/liouzhou_101\" title=\"International Master liouzhou_101\" class=\"rated-user user-orange\">liouzhou_101</a> →\r\n <a href=\"/blog/entry/87598\">Editorial of Codeforces Round #700</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/yeon_gist\" title=\"Newbie yeon_gist\" class=\"rated-user user-gray\">yeon_gist</a> →\r\n <a href=\"/blog/entry/121170\">plusMinusPermutation computing error</a>\r\n <img alt=\"Text created or updated\" title=\"Text created or updated\" src=\"//codeforces.org/s/81027/images/icons/x-update-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/altforminuscontribution\" title=\"Newbie altforminuscontribution\" class=\"rated-user user-gray\">altforminuscontribution</a> →\r\n <a href=\"/blog/entry/121162\">My screen get unexpectedly big, what should I do</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/atcoder_official\" title=\"Unrated, atcoder_official\" class=\"rated-user user-black\">atcoder_official</a> →\r\n <a href=\"/blog/entry/121120\">We will hold UNIQUE VISION Programming Contest 2023 Autumn(AtCoder Beginner Contest 323)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/YouStill_DontKnowMeYet\" title=\"Candidate Master YouStill_DontKnowMeYet\" class=\"rated-user user-violet\">YouStill_DontKnowMeYet</a> →\r\n <a href=\"/blog/entry/117659\">[GYM] Al-Baath Collegiate Programming Contest 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/ankancool\" title=\"Expert ankancool\" class=\"rated-user user-blue\">ankancool</a> →\r\n <a href=\"/blog/entry/121136\">Invitation to AstroByte 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/GeZhiyuan\" title=\"Grandmaster GeZhiyuan\" class=\"rated-user user-red\">GeZhiyuan</a> →\r\n <a href=\"/blog/entry/120943\">Codeforces Round 901 (Div. 1, Div. 2) Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a> →\r\n <a href=\"/blog/entry/120772\">PSA: Increase your stack size before the Meta Hacker Cup, here's how</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/dino_merlin\" title=\"Expert dino_merlin\" class=\"rated-user user-blue\">dino_merlin</a> →\r\n <a href=\"/blog/entry/121145\">Intuitive approach for CEOI Kangaroo?</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/icecuber\" title=\"Grandmaster icecuber\" class=\"rated-user user-red\">icecuber</a> →\r\n <a href=\"/blog/entry/70018\">CSES DP section editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bn00b\" title=\"Newbie Bn00b\" class=\"rated-user user-gray\">Bn00b</a> →\r\n <a href=\"/blog/entry/98820\">[FEATURE REQUEST : ATCODER] TOPICS TAGS AND SORTING BY SOLVE COUNT</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a> →\r\n <a href=\"/blog/entry/121163\">AtCoder Regular Contest 166 Announcement</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/windva\" title=\"Grandmaster windva\" class=\"rated-user user-red\">windva</a> →\r\n <a href=\"/blog/entry/120644\">Codeforces Round 899 (Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Misa-Misa\" title=\"Expert Misa-Misa\" class=\"rated-user user-blue\">Misa-Misa</a> →\r\n <a href=\"/blog/entry/121157\">Someone please help me understand this.</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/shivam565\" title=\"Specialist shivam565\" class=\"rated-user user-cyan\">shivam565</a> →\r\n <a href=\"/blog/entry/108348\">Total number of subarrays with sum atmost k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n </ul>\r\n </div>\r\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/recent-actions\">Detailed →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n</div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li><a\r\n href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"773\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/773\"> Codeforces Beta Round #36 (Problem E solution)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/20/2010 20:10\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">The problem is to divide edges of a graph into two groups forming two paths in the graph. Clearly, each path is contained in one connected component. So if the given graph has more than two connected components, the problem has no solution. The same we can say if the graph has more than four vertices of an odd degree. Indeed, each vertex in a path (even if the path contains some vertices more than once) have an even degree, exept the first vertex and the last vertex. So the union of two paths can contain no more than four odd vertices.<div><br /></div><div>Now consider the cases:</div><div><br /></div><div>1. One connected component, no vertices of an odd degree. So we have an euler cycle, which can be divided into two paths.</div><div><br /></div><div>2. One connected component, two odd vertices. The same with an euler path instead of euler cycle. There is a tricky case of a graph with only one edge, which cannot be divided into two nonempty paths.</div><div><br /></div><div>3. One connected component, four odd vertices. The most interesting case. Connect two vertices of an odd degree by a dummy edge. You will get a graph with an euler path. Find the euler path and delete the dummy edge - you will get two paths.</div><div><br /></div><div>4. Two connetced components, each having zero or two odd vertices. Two euler paths/cycles.</div><div><br /></div><div>5. Two connected components, four odd vertices in one and no odd vertices in another. No solution.</div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/36\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 36</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-773\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"773\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2336\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #36</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-773\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" 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href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/20/2010 20:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/773#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/773#comments\">\n 0\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments 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Towers"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Towers</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Little Vasya has received a young builder’s kit. The kit consists of several wooden bars, the lengths of all of them are known. The bars can be put one on the top of the other if their lengths are the same.</p><p>Vasya wants to construct the minimal number of towers from the bars. Help Vasya to use the bars in the best way possible.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>N</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i> ≤ 1000</span>) — the number of bars at Vasya’s disposal. The second line contains <span class=\"tex-span\"><i>N</i></span> space-separated integers <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span> — the lengths of the bars. All the lengths are natural numbers not exceeding <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In one line output two numbers — the height of the largest tower and their total number. Remember that Vasya should use all the bars.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>1 2 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>6 5 6 7<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 3<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"7303d7438efcdd19abc6a30c8c27a6ea\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"9ca010b5bc88a84f6e5bf74687b257a83dd1ef91\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/37\">Codeforces Beta Round 37</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Sortings, orderings\">\r\n sortings\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1000\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='7303d7438efcdd19abc6a30c8c27a6ea'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"185\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='7303d7438efcdd19abc6a30c8c27a6ea'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"185\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/792\" title=\"Codeforces Beta Round #37\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"156:157\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/798\" title=\"Codeforces Beta Round #37 (Tutorial)\" target=\"_blank\">Tutorial</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"547:548\" resourceName=\"Tutorial\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n 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</div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Towers</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Little Vasya has received a young builder’s kit. The kit consists of several wooden bars, the lengths of all of them are known. The bars can be put one on the top of the other if their lengths are the same.</p><p>Vasya wants to construct the minimal number of towers from the bars. Help Vasya to use the bars in the best way possible.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>N</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i> ≤ 1000</span>) — the number of bars at Vasya’s disposal. The second line contains <span class=\"tex-span\"><i>N</i></span> space-separated integers <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span> — the lengths of the bars. All the lengths are natural numbers not exceeding <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In one line output two numbers — the height of the largest tower and their total number. Remember that Vasya should use all the bars.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />1 2 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />6 5 6 7<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 3<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=A]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n 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class='input-output-copier'>Copy</div>\");\r\n $(this).append($copy);\r\n\r\n const clipboard = new Clipboard('#' + cpyId, {\r\n text: function (trigger) {\r\n const pre = document.querySelector('#' + preId);\r\n const lines = pre.querySelectorAll(\".test-example-line\");\r\n return Codeforces.filterClipboardText(pre.innerText, lines.length);\r\n }\r\n });\r\n\r\n const isInput = $(this).parent().hasClass(\"input\");\r\n\r\n clipboard.on('success', function (e) {\r\n if (isInput) {\r\n Codeforces.showMessage(\"The example input has been copied into the clipboard\");\r\n } else {\r\n Codeforces.showMessage(\"The example output has been copied into the clipboard\");\r\n }\r\n e.clearSelection();\r\n });\r\n });\r\n\r\n $(\".test-form-item input\").change(function () {\r\n addPendingSubmissionMessage($($(this).closest(\"form\")), \"You changed the answer, do not forget to submit it if you want to save the changes\");\r\n const index = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:06</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='0ab0f791e5640a29e183082a8066264f'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n </label>\r\n </div>\r\n <div style=\"padding: 0 1em 1em 1em;text-align:right;\">\r\n <input style=\"height:1.65em;padding:0 0.75em;\" type=\"submit\" value=\"Find\"/>\r\n </div>\r\n </form>\r\n </div>\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".handleBox\").autocomplete(\"/data/handles\", {\r\n delay: 200,\r\n width: 200,\r\n selectFirst: false,\r\n matchContains: true,\r\n minChars: 3\r\n });\r\n $(\".handleForm\").attr(\"autocomplete\", \"off\").submit(function () {\r\n var link = \"/profile/userHandle\".replace(\r\n \"userHandle\", $(this).find(\".handleBox\").val()\r\n );\r\n window.location = link;\r\n return false;\r\n });\r\n });\n </script>\n\r\n\r\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Recent actions\n <div class=\"top-links\">\n </div>\n </div>\n <div class=\"recent-actions\">\r\n <ul>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a href=\"/blog/entry/121171\">An Interesting Tree Problem</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/.Danet\" title=\"Expert .Danet\" class=\"rated-user user-blue\">.Danet</a> →\r\n <a href=\"/blog/entry/121172\">[TLE on pretest1]</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/sszcdjr\" title=\"Master sszcdjr\" class=\"rated-user user-orange\">sszcdjr</a> →\r\n <a href=\"/blog/entry/119859\">Codeforces Round 896 (Div. 1, Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" 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href=\"/profile/vepifanov\">vepifanov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/vepifanov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/vepifanov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/vepifanov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/vepifanov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/vepifanov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/vepifanov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/vepifanov\" style=\"text-decoration:none;color:black !important;\">vepifanov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"798\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/798\"> Codeforces Beta Round #37 (Tutorial)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a>,\r\n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><b>A. Towers</b><br /> <span lang=\"en\"><span style=\"color: rgb(0,0,0);\" title=\"\">The total number of towers is equal to number of different numbers in this set. </span><span style=\"\" title=\"\">To get the maximum height of the tower, it was possible to calculate for each length the number of bars with this length, and from these numbers is to choose the maximum.</span></span><br /> <br /> <b>B. Computer Game</b><br /> <span lang=\"en\"><span title=\"\">Constraints in the problem allows us to solve it this way: we keep the current number of health from the boss, and current summary damage from used scrolls per second. </span><span style=\"\" title=\"\">At the next step, we choose which scrolls we can use in the current second. </span><span style=\"\" title=\"\">Of all these, we find the scroll, which causes the most damage, and apply it. </span><span style=\"\" title=\"\">If at some point we could not use any of the scrolls, and the current damage in one second does not exceed regeneration, we deduce that there are no answers. </span><span style=\"\" title=\"\">Otherwise, continue to iterate the algorithm until the number hit points will be nonnegative.</span></span><br /> <br /> <b>C. Old Berland Language</b><br /><span lang=\"en\"><span style=\"\" title=\"\">One of the easiest to understand solutions of this problem is as follows: sort the words in ascending order of length, while remembering their positions in the source list. </span><span style=\"\" title=\"\">We will consistently build our set, starting with the short strings: strings of length one can only be strings "0" and "1". </span><span style=\"\" title=\"\">If the number of words of length one in a set are more than two, hence there are no answers. </span><span style=\"\" title=\"\">Add the desired number of strings of length one to answer, and remove it from the current list. </span><span style=\"\" title=\"\">Then look at the string of length two: each of the remaining strings of length one can be extended in two ways (having added to each of these symbols 0 and 1). </span><span style=\"\" title=\"\">Add the desired number of strings of length two in our answer, and then increase the length of the remaining strings by one.</span><span style=\"\" title=\"\"> Continue this process, </span></span><span lang=\"en\"><span style=\"\" title=\"\">until we get all words from the input set</span></span><span lang=\"en\"><span style=\"\" title=\"\">. </span><span style=\"\" title=\"\">You can see that if at some moment the number of allowable words exceeded the number of remaining, the extra words can be ignored and solution takes </span></span><span lang=\"en\"><span style=\"\" title=\"\">O (N * the maximum length of input set) time.</span></span> <br /></p> <p><b>D. Lesson Timetable<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">This problem is solved by dynamic programming:<br /><br /></span><span style=\"\" title=\"\">state of dynamics will be a pair of numbers - the number of current room and number of groups which have first lesson in the room with a number not exceeding the current and for which the second room is not defined yet. </span><span style=\"\" title=\"\">For each state check all possible number of groups for which the second lesson will be held in the current classroom. </span><span style=\"\" title=\"\">When you add an answer from the new state, it must be multiplied by the corresponding binomial coefficients (the number of ways to select groups which have the first lesson in next room - <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub> + 1</span>, and the number of ways to select groups which have the second lesson</span></span><span lang=\"en\"><span style=\"\" title=\"\"> in the current classroom).</span></span><p> </p> <p><b>E. Trial for Chief<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">First, we construct the following graph: each cell we associate a vertex of the same color as the cell itself. </span><span style=\"\" title=\"\">Between neighboring cells hold an edge of weight 0, if the cells share the same color and weight of 1, if different. </span><span style=\"\" title=\"\">Now, for each cell count the shortest distance from it to the most distant black cell (denoted by <span class=\"tex-span\"><i>D</i></span>). </span><span style=\"\" title=\"\">It is easy to see that we can construct a sequence of <span class=\"tex-span\"><i>D</i> + 1</span> repainting leads to the desired coloring:<br /><br /></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\"></span><span style=\"\" title=\"\">The first step of color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i></span> in black color</span></span><br /></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\">At the second step color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i> - 1</span> in white</span></span></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span title=\"\">Etc.</span></span></li></ul><span lang=\"en\"><span title=\"\"><br /></span><span style=\"\" title=\"\">Of all the cells, choose the one for which this distance is minimal, and this distance increased by one will be the answer to the problem.</span></span></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/37\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 37</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2424-798\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2424\",\n blogEntryId: \"798\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2337\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #37</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+32</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/vepifanov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/vepifanov\">\n vepifanov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/798#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/798#comments\">\n 6\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"808\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (6)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13074\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/t__nt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/134/avatar/2584a6760a294637.jpg'/> </a>\n <div><a href=\"/profile/t__nt\" title=\"Master t__nt\" class=\"rated-user user-orange\">t__nt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 06:52\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13074\" href=\"?#comment-13074\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13074\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"134\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13074\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In the tutorial of Problem E, the way to paint the cells is brilliant. Meanwhile finding the cell to minimize D is just to optimize the solution in this way.<div>But how to prove that this method you paint the cells is the best? Thank you very much.</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13074 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13074 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13074\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13093\" commentParentId=\"13074\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 16:55\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13093\" href=\"?#comment-13093\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13074\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13093\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13093\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13093\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><span lang=\"en\"><span style=\"\" title=\"\">The proof is in short looks like this:<br /><br /></span><span style=\"\" title=\"\">First, compress all vertices between which distance is equal to zero in one component (get graph of connected components).<br /></span><span style=\"\" title=\"\">Note that if we repaint some cell, it can be repainted and all its component, as a result coloring will not change.<br /><br /></span><span style=\"\" title=\"\">1) we can prove that any coloring can be reduced to a form such that each subsequent repainting is a subset of the previous one.<br /></span><span style=\"\" title=\"\">2) the last repainting will consist of exactly one vertex (possibly the whole monochromatic connected region of the original board).<br /><br /></span><span style=\"\" title=\"\">Therefore, one of the best answers will be of the form described in the review. </span><span style=\"\" title=\"\">If as the initial vertex, we take a cell, lying in the last repainting of the optimal sequence, the algorithm finds the solution not worse than optimal.</span></span><div style=\"\"><div style=\"display: none;\"><span><span>Прослушать</span></span></div><div style=\"display: none;\"><span><span>На латинице</span></span></div><br /></div></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13093 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13093 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13093\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13076\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/samshu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/5855/avatar/2016640288859ccd.jpg'/> </a>\n <div><a href=\"/profile/samshu\" title=\"Newbie samshu\" class=\"rated-user user-gray\">samshu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 09:47\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13076\" href=\"?#comment-13076\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13076\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"5855\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13076\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I tried to simulate exactly the algorithm described for Problem C, but it obviously times out since it requires a huge memory space. Can anybody tell me how do i optimize it? I've posted my solution here -<br />http://ideone.com/il8Do</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13076 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13076 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13076\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13077\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/DStepanenko\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/DStepanenko\" title=\"Expert DStepanenko\" class=\"rated-user user-blue\">DStepanenko</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:16\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13077\" href=\"?#comment-13077\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13077\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"309\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13077\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Хотелось бы чтобы отписались люди, сдавшие эту задачу и имеющие альтернативные решения.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13077 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13077 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13077\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13079\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:36\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13079\" href=\"?#comment-13079\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13079\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13079\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13079\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Well, my solution doesn't need any memory at all. Process the lengths of the words in increasing order and try to find lexicographically smallest word at each step. Suppose <i>s</i> is the last word written out, and its length is <i>k</i>. Then all strings that have length <i>k</i> and are lexicographically not larger than <i>s</i>, are 'bad' (each of them has a prefix that is already written out). So, to find out the <i>k</i>-prefix of the next word we need to increase <i>s</i> by 1 (as a binary number). Obviously, if <i>s</i> consists of 1's it's impossible, since we will get a word of length <i>k</i>+1. Now we need to find lexicographically smallest encoding of the next word. To do that, just add zeros to the increased value of <i>s</i>.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13079 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13079 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13079\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13095\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 17:10\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13095\" href=\"?#comment-13095\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13095\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13095\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">This is solution of problem C from tutorial: <br />http://ideone.com/lHtSZ</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13095 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13095 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n 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Computer Game"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Computer Game</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya’s elder brother Petya loves playing computer games. In one of his favourite computer games Petya reached the final level where a fight with the boss take place.</p><p>While playing the game Petya found spell scrolls and now he is about to use them. Let’s describe the way fighting goes on this level:</p><p>1) The boss has two parameters: <span class=\"tex-span\"><i>max</i></span> — the initial amount of health and <span class=\"tex-span\"><i>reg</i></span> — regeneration rate per second.</p><p>2) Every scroll also has two parameters: <span class=\"tex-span\"><i>pow</i><sub class=\"lower-index\"><i>i</i></sub></span> — spell power measured in percents — the maximal amount of health counted off the initial one, which allows to use the scroll (i.e. if the boss has more than <span class=\"tex-span\"><i>pow</i><sub class=\"lower-index\"><i>i</i></sub></span> percent of health the scroll cannot be used); and <span class=\"tex-span\"><i>dmg</i><sub class=\"lower-index\"><i>i</i></sub></span> the damage per second inflicted upon the boss if the scroll is used. As soon as a scroll is used it disappears and another spell is cast upon the boss that inflicts <span class=\"tex-span\"><i>dmg</i><sub class=\"lower-index\"><i>i</i></sub></span> of damage per second upon him until the end of the game.</p><p>During the battle the actions per second are performed in the following order: first the boss gets the damage from all the spells cast upon him, then he regenerates <span class=\"tex-span\"><i>reg</i></span> of health (at the same time he can’t have more than <span class=\"tex-span\"><i>max</i></span> of health), then the player may use another scroll (no more than one per second).</p><p>The boss is considered to be defeated if at the end of a second he has nonpositive (<span class=\"tex-span\"> ≤ 0</span>) amount of health.</p><p>Help Petya to determine whether he can win with the set of scrolls available to him and if he can, determine the minimal number of seconds he needs to do it.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three integers <span class=\"tex-span\"><i>N</i></span>, <span class=\"tex-span\"><i>max</i></span> and <span class=\"tex-span\"><i>reg</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i>, <i>max</i>, <i>reg</i> ≤ 1000</span>) –– the amount of scrolls and the parameters of the boss. The next <span class=\"tex-span\"><i>N</i></span> lines contain two integers <span class=\"tex-span\"><i>pow</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>dmg</i><sub class=\"lower-index\"><i>i</i></sub></span> each — the parameters of the <span class=\"tex-span\"><i>i</i></span>-th scroll (<span class=\"tex-span\">0 ≤ <i>pow</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>, <span class=\"tex-span\">1 ≤ <i>dmg</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 2000</span>). </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In case Petya can’t complete this level, output in the single line <span class=\"tex-font-style-tt\">NO</span>.</p><p>Otherwise, output on the first line <span class=\"tex-font-style-tt\">YES</span>. On the second line output the minimal time after which the boss can be defeated and the number of used scrolls. In the next lines for each used scroll output space-separated number of seconds passed from the start of the battle to the moment the scroll was used and the number of the scroll. Scrolls are numbered starting from 1 in the input order. The first scroll is considered to be available to be used after <span class=\"tex-span\">0</span> seconds.</p><p>Output scrolls in the order they were used. It is not allowed to use scrolls after the boss is defeated.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 10 3<br/>100 3<br/>99 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 100 10<br/>100 11<br/>90 9<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/>19 2<br/>0 1<br/>10 2<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"7691c07f7f00067ef227c09192fdc813\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"9ca010b5bc88a84f6e5bf74687b257a83dd1ef91\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='7691c07f7f00067ef227c09192fdc813'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/37/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Greedy algorithms\">\r\n greedy\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1800\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='7691c07f7f00067ef227c09192fdc813'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"186\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='7691c07f7f00067ef227c09192fdc813'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"186\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/792\" title=\"Codeforces Beta Round #37\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"156:157\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/798\" title=\"Codeforces Beta Round #37 (Tutorial)\" target=\"_blank\">Tutorial</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"547:548\" 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|| c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"B\" data-uuid=\"ps_942b6b0c8a8d74bcdeaf97f09633b14103897715\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Computer Game</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya’s elder brother Petya loves playing computer games. In one of his favourite computer games Petya reached the final level where a fight with the boss take place.</p><p>While playing the game Petya found spell scrolls and now he is about to use them. Let’s describe the way fighting goes on this level:</p><p>1) The boss has two parameters: <span class=\"tex-span\"><i>max</i></span> — the initial amount of health and <span class=\"tex-span\"><i>reg</i></span> — regeneration rate per second.</p><p>2) Every scroll also has two parameters: <span class=\"tex-span\"><i>pow</i><sub class=\"lower-index\"><i>i</i></sub></span> — spell power measured in percents — the maximal amount of health counted off the initial one, which allows to use the scroll (i.e. if the boss has more than <span class=\"tex-span\"><i>pow</i><sub class=\"lower-index\"><i>i</i></sub></span> percent of health the scroll cannot be used); and <span class=\"tex-span\"><i>dmg</i><sub class=\"lower-index\"><i>i</i></sub></span> the damage per second inflicted upon the boss if the scroll is used. As soon as a scroll is used it disappears and another spell is cast upon the boss that inflicts <span class=\"tex-span\"><i>dmg</i><sub class=\"lower-index\"><i>i</i></sub></span> of damage per second upon him until the end of the game.</p><p>During the battle the actions per second are performed in the following order: first the boss gets the damage from all the spells cast upon him, then he regenerates <span class=\"tex-span\"><i>reg</i></span> of health (at the same time he can’t have more than <span class=\"tex-span\"><i>max</i></span> of health), then the player may use another scroll (no more than one per second).</p><p>The boss is considered to be defeated if at the end of a second he has nonpositive (<span class=\"tex-span\"> ≤ 0</span>) amount of health.</p><p>Help Petya to determine whether he can win with the set of scrolls available to him and if he can, determine the minimal number of seconds he needs to do it.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three integers <span class=\"tex-span\"><i>N</i></span>, <span class=\"tex-span\"><i>max</i></span> and <span class=\"tex-span\"><i>reg</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i>, <i>max</i>, <i>reg</i> ≤ 1000</span>) –– the amount of scrolls and the parameters of the boss. The next <span class=\"tex-span\"><i>N</i></span> lines contain two integers <span class=\"tex-span\"><i>pow</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>dmg</i><sub class=\"lower-index\"><i>i</i></sub></span> each — the parameters of the <span class=\"tex-span\"><i>i</i></span>-th scroll (<span class=\"tex-span\">0 ≤ <i>pow</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>, <span class=\"tex-span\">1 ≤ <i>dmg</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 2000</span>). </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In case Petya can’t complete this level, output in the single line <span class=\"tex-font-style-tt\">NO</span>.</p><p>Otherwise, output on the first line <span class=\"tex-font-style-tt\">YES</span>. On the second line output the minimal time after which the boss can be defeated and the number of used scrolls. In the next lines for each used scroll output space-separated number of seconds passed from the start of the battle to the moment the scroll was used and the number of the scroll. Scrolls are numbered starting from 1 in the input order. The first scroll is considered to be available to be used after <span class=\"tex-span\">0</span> seconds.</p><p>Output scrolls in the order they were used. It is not allowed to use scrolls after the boss is defeated.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 10 3<br />100 3<br />99 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 100 10<br />100 11<br />90 9<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br />19 2<br />0 1<br />10 2<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=B]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='0ab0f791e5640a29e183082a8066264f'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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href=\"/profile/vepifanov\">vepifanov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/vepifanov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/vepifanov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/vepifanov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/vepifanov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/vepifanov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/vepifanov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/vepifanov\" style=\"text-decoration:none;color:black !important;\">vepifanov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"798\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/798\"> Codeforces Beta Round #37 (Tutorial)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a>,\r\n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><b>A. Towers</b><br /> <span lang=\"en\"><span style=\"color: rgb(0,0,0);\" title=\"\">The total number of towers is equal to number of different numbers in this set. </span><span style=\"\" title=\"\">To get the maximum height of the tower, it was possible to calculate for each length the number of bars with this length, and from these numbers is to choose the maximum.</span></span><br /> <br /> <b>B. Computer Game</b><br /> <span lang=\"en\"><span title=\"\">Constraints in the problem allows us to solve it this way: we keep the current number of health from the boss, and current summary damage from used scrolls per second. </span><span style=\"\" title=\"\">At the next step, we choose which scrolls we can use in the current second. </span><span style=\"\" title=\"\">Of all these, we find the scroll, which causes the most damage, and apply it. </span><span style=\"\" title=\"\">If at some point we could not use any of the scrolls, and the current damage in one second does not exceed regeneration, we deduce that there are no answers. </span><span style=\"\" title=\"\">Otherwise, continue to iterate the algorithm until the number hit points will be nonnegative.</span></span><br /> <br /> <b>C. Old Berland Language</b><br /><span lang=\"en\"><span style=\"\" title=\"\">One of the easiest to understand solutions of this problem is as follows: sort the words in ascending order of length, while remembering their positions in the source list. </span><span style=\"\" title=\"\">We will consistently build our set, starting with the short strings: strings of length one can only be strings "0" and "1". </span><span style=\"\" title=\"\">If the number of words of length one in a set are more than two, hence there are no answers. </span><span style=\"\" title=\"\">Add the desired number of strings of length one to answer, and remove it from the current list. </span><span style=\"\" title=\"\">Then look at the string of length two: each of the remaining strings of length one can be extended in two ways (having added to each of these symbols 0 and 1). </span><span style=\"\" title=\"\">Add the desired number of strings of length two in our answer, and then increase the length of the remaining strings by one.</span><span style=\"\" title=\"\"> Continue this process, </span></span><span lang=\"en\"><span style=\"\" title=\"\">until we get all words from the input set</span></span><span lang=\"en\"><span style=\"\" title=\"\">. </span><span style=\"\" title=\"\">You can see that if at some moment the number of allowable words exceeded the number of remaining, the extra words can be ignored and solution takes </span></span><span lang=\"en\"><span style=\"\" title=\"\">O (N * the maximum length of input set) time.</span></span> <br /></p> <p><b>D. Lesson Timetable<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">This problem is solved by dynamic programming:<br /><br /></span><span style=\"\" title=\"\">state of dynamics will be a pair of numbers - the number of current room and number of groups which have first lesson in the room with a number not exceeding the current and for which the second room is not defined yet. </span><span style=\"\" title=\"\">For each state check all possible number of groups for which the second lesson will be held in the current classroom. </span><span style=\"\" title=\"\">When you add an answer from the new state, it must be multiplied by the corresponding binomial coefficients (the number of ways to select groups which have the first lesson in next room - <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub> + 1</span>, and the number of ways to select groups which have the second lesson</span></span><span lang=\"en\"><span style=\"\" title=\"\"> in the current classroom).</span></span><p> </p> <p><b>E. Trial for Chief<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">First, we construct the following graph: each cell we associate a vertex of the same color as the cell itself. </span><span style=\"\" title=\"\">Between neighboring cells hold an edge of weight 0, if the cells share the same color and weight of 1, if different. </span><span style=\"\" title=\"\">Now, for each cell count the shortest distance from it to the most distant black cell (denoted by <span class=\"tex-span\"><i>D</i></span>). </span><span style=\"\" title=\"\">It is easy to see that we can construct a sequence of <span class=\"tex-span\"><i>D</i> + 1</span> repainting leads to the desired coloring:<br /><br /></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\"></span><span style=\"\" title=\"\">The first step of color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i></span> in black color</span></span><br /></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\">At the second step color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i> - 1</span> in white</span></span></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span title=\"\">Etc.</span></span></li></ul><span lang=\"en\"><span title=\"\"><br /></span><span style=\"\" title=\"\">Of all the cells, choose the one for which this distance is minimal, and this distance increased by one will be the answer to the problem.</span></span></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/37\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 37</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2424-798\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2424\",\n blogEntryId: \"798\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2337\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #37</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+32</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/vepifanov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/vepifanov\">\n vepifanov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/798#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/798#comments\">\n 6\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"808\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (6)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13074\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/t__nt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/134/avatar/2584a6760a294637.jpg'/> </a>\n <div><a href=\"/profile/t__nt\" title=\"Master t__nt\" class=\"rated-user user-orange\">t__nt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 06:52\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13074\" href=\"?#comment-13074\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13074\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"134\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13074\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In the tutorial of Problem E, the way to paint the cells is brilliant. Meanwhile finding the cell to minimize D is just to optimize the solution in this way.<div>But how to prove that this method you paint the cells is the best? Thank you very much.</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13074 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13074 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13074\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13093\" commentParentId=\"13074\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 16:55\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13093\" href=\"?#comment-13093\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13074\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13093\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13093\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13093\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><span lang=\"en\"><span style=\"\" title=\"\">The proof is in short looks like this:<br /><br /></span><span style=\"\" title=\"\">First, compress all vertices between which distance is equal to zero in one component (get graph of connected components).<br /></span><span style=\"\" title=\"\">Note that if we repaint some cell, it can be repainted and all its component, as a result coloring will not change.<br /><br /></span><span style=\"\" title=\"\">1) we can prove that any coloring can be reduced to a form such that each subsequent repainting is a subset of the previous one.<br /></span><span style=\"\" title=\"\">2) the last repainting will consist of exactly one vertex (possibly the whole monochromatic connected region of the original board).<br /><br /></span><span style=\"\" title=\"\">Therefore, one of the best answers will be of the form described in the review. </span><span style=\"\" title=\"\">If as the initial vertex, we take a cell, lying in the last repainting of the optimal sequence, the algorithm finds the solution not worse than optimal.</span></span><div style=\"\"><div style=\"display: none;\"><span><span>Прослушать</span></span></div><div style=\"display: none;\"><span><span>На латинице</span></span></div><br /></div></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13093 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13093 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13093\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13076\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/samshu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/5855/avatar/2016640288859ccd.jpg'/> </a>\n <div><a href=\"/profile/samshu\" title=\"Newbie samshu\" class=\"rated-user user-gray\">samshu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 09:47\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13076\" href=\"?#comment-13076\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13076\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"5855\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13076\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I tried to simulate exactly the algorithm described for Problem C, but it obviously times out since it requires a huge memory space. Can anybody tell me how do i optimize it? I've posted my solution here -<br />http://ideone.com/il8Do</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13076 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13076 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13076\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13077\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/DStepanenko\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/DStepanenko\" title=\"Expert DStepanenko\" class=\"rated-user user-blue\">DStepanenko</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:16\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13077\" href=\"?#comment-13077\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13077\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"309\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13077\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Хотелось бы чтобы отписались люди, сдавшие эту задачу и имеющие альтернативные решения.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13077 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13077 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13077\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13079\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:36\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13079\" href=\"?#comment-13079\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13079\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13079\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13079\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Well, my solution doesn't need any memory at all. Process the lengths of the words in increasing order and try to find lexicographically smallest word at each step. Suppose <i>s</i> is the last word written out, and its length is <i>k</i>. Then all strings that have length <i>k</i> and are lexicographically not larger than <i>s</i>, are 'bad' (each of them has a prefix that is already written out). So, to find out the <i>k</i>-prefix of the next word we need to increase <i>s</i> by 1 (as a binary number). Obviously, if <i>s</i> consists of 1's it's impossible, since we will get a word of length <i>k</i>+1. Now we need to find lexicographically smallest encoding of the next word. To do that, just add zeros to the increased value of <i>s</i>.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13079 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13079 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13079\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13095\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 17:10\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13095\" href=\"?#comment-13095\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13095\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13095\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">This is solution of problem C from tutorial: <br />http://ideone.com/lHtSZ</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13095 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13095 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n 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Old Berland Language"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Old Berland Language</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Berland scientists know that the Old Berland language had exactly <span class=\"tex-span\"><i>n</i></span> words. Those words had lengths of <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\">1</sub>, <i>l</i><sub class=\"lower-index\">2</sub>, ..., <i>l</i><sub class=\"lower-index\"><i>n</i></sub></span> letters. Every word consisted of two letters, <span class=\"tex-span\">0</span> and <span class=\"tex-span\">1</span>. Ancient Berland people spoke quickly and didn’t make pauses between the words, but at the same time they could always understand each other perfectly. It was possible because no word was a prefix of another one. The prefix of a string is considered to be one of its substrings that starts from the initial symbol.</p><p>Help the scientists determine whether all the words of the Old Berland language can be reconstructed and if they can, output the words themselves.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains one integer <span class=\"tex-span\"><i>N</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i> ≤ 1000</span>) — the number of words in Old Berland language. The second line contains <span class=\"tex-span\"><i>N</i></span> space-separated integers — the lengths of these words. All the lengths are natural numbers not exceeding <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>If there’s no such set of words, in the single line output <span class=\"tex-font-style-tt\">NO</span>. Otherwise, in the first line output <span class=\"tex-font-style-tt\">YES</span>, and in the next <span class=\"tex-span\"><i>N</i></span> lines output the words themselves in the order their lengths were given in the input file. If the answer is not unique, output any.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>1 2 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/>0<br/>10<br/>110<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>1 1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"0c616dd1b16779bdca7fe1e0b5add854\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"9ca010b5bc88a84f6e5bf74687b257a83dd1ef91\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/37\">Codeforces Beta Round 37</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/37/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Heaps, binary search trees, segment trees, hash tables, etc\">\r\n data structures\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Greedy algorithms\">\r\n greedy\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Trees\">\r\n trees\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1900\r\n</span>\r\n 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{\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/792\" title=\"Codeforces Beta Round #37\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"156:157\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/798\" title=\"Codeforces Beta Round #37 (Tutorial)\" target=\"_blank\">Tutorial</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"547:548\" resourceName=\"Tutorial\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/37\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/37/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/37/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/37/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/37/hacks\">Hacks</a></li>\r\n 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value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"C\" data-uuid=\"ps_307f35a1d5f9dcb29d15d1591c69fc7bac591f5d\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Old Berland Language</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Berland scientists know that the Old Berland language had exactly <span class=\"tex-span\"><i>n</i></span> words. Those words had lengths of <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\">1</sub>, <i>l</i><sub class=\"lower-index\">2</sub>, ..., <i>l</i><sub class=\"lower-index\"><i>n</i></sub></span> letters. Every word consisted of two letters, <span class=\"tex-span\">0</span> and <span class=\"tex-span\">1</span>. Ancient Berland people spoke quickly and didn’t make pauses between the words, but at the same time they could always understand each other perfectly. It was possible because no word was a prefix of another one. The prefix of a string is considered to be one of its substrings that starts from the initial symbol.</p><p>Help the scientists determine whether all the words of the Old Berland language can be reconstructed and if they can, output the words themselves.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains one integer <span class=\"tex-span\"><i>N</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i> ≤ 1000</span>) — the number of words in Old Berland language. The second line contains <span class=\"tex-span\"><i>N</i></span> space-separated integers — the lengths of these words. All the lengths are natural numbers not exceeding <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>If there’s no such set of words, in the single line output <span class=\"tex-font-style-tt\">NO</span>. Otherwise, in the first line output <span class=\"tex-font-style-tt\">YES</span>, and in the next <span class=\"tex-span\"><i>N</i></span> lines output the words themselves in the order their lengths were given in the input file. If the answer is not unique, output any.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />1 2 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br />0<br />10<br />110<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />1 1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='0ab0f791e5640a29e183082a8066264f'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/vepifanov\">vepifanov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/vepifanov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/vepifanov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/vepifanov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/vepifanov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/vepifanov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/vepifanov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/vepifanov\" style=\"text-decoration:none;color:black !important;\">vepifanov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"798\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/798\"> Codeforces Beta Round #37 (Tutorial)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a>,\r\n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><b>A. Towers</b><br /> <span lang=\"en\"><span style=\"color: rgb(0,0,0);\" title=\"\">The total number of towers is equal to number of different numbers in this set. </span><span style=\"\" title=\"\">To get the maximum height of the tower, it was possible to calculate for each length the number of bars with this length, and from these numbers is to choose the maximum.</span></span><br /> <br /> <b>B. Computer Game</b><br /> <span lang=\"en\"><span title=\"\">Constraints in the problem allows us to solve it this way: we keep the current number of health from the boss, and current summary damage from used scrolls per second. </span><span style=\"\" title=\"\">At the next step, we choose which scrolls we can use in the current second. </span><span style=\"\" title=\"\">Of all these, we find the scroll, which causes the most damage, and apply it. </span><span style=\"\" title=\"\">If at some point we could not use any of the scrolls, and the current damage in one second does not exceed regeneration, we deduce that there are no answers. </span><span style=\"\" title=\"\">Otherwise, continue to iterate the algorithm until the number hit points will be nonnegative.</span></span><br /> <br /> <b>C. Old Berland Language</b><br /><span lang=\"en\"><span style=\"\" title=\"\">One of the easiest to understand solutions of this problem is as follows: sort the words in ascending order of length, while remembering their positions in the source list. </span><span style=\"\" title=\"\">We will consistently build our set, starting with the short strings: strings of length one can only be strings "0" and "1". </span><span style=\"\" title=\"\">If the number of words of length one in a set are more than two, hence there are no answers. </span><span style=\"\" title=\"\">Add the desired number of strings of length one to answer, and remove it from the current list. </span><span style=\"\" title=\"\">Then look at the string of length two: each of the remaining strings of length one can be extended in two ways (having added to each of these symbols 0 and 1). </span><span style=\"\" title=\"\">Add the desired number of strings of length two in our answer, and then increase the length of the remaining strings by one.</span><span style=\"\" title=\"\"> Continue this process, </span></span><span lang=\"en\"><span style=\"\" title=\"\">until we get all words from the input set</span></span><span lang=\"en\"><span style=\"\" title=\"\">. </span><span style=\"\" title=\"\">You can see that if at some moment the number of allowable words exceeded the number of remaining, the extra words can be ignored and solution takes </span></span><span lang=\"en\"><span style=\"\" title=\"\">O (N * the maximum length of input set) time.</span></span> <br /></p> <p><b>D. Lesson Timetable<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">This problem is solved by dynamic programming:<br /><br /></span><span style=\"\" title=\"\">state of dynamics will be a pair of numbers - the number of current room and number of groups which have first lesson in the room with a number not exceeding the current and for which the second room is not defined yet. </span><span style=\"\" title=\"\">For each state check all possible number of groups for which the second lesson will be held in the current classroom. </span><span style=\"\" title=\"\">When you add an answer from the new state, it must be multiplied by the corresponding binomial coefficients (the number of ways to select groups which have the first lesson in next room - <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub> + 1</span>, and the number of ways to select groups which have the second lesson</span></span><span lang=\"en\"><span style=\"\" title=\"\"> in the current classroom).</span></span><p> </p> <p><b>E. Trial for Chief<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">First, we construct the following graph: each cell we associate a vertex of the same color as the cell itself. </span><span style=\"\" title=\"\">Between neighboring cells hold an edge of weight 0, if the cells share the same color and weight of 1, if different. </span><span style=\"\" title=\"\">Now, for each cell count the shortest distance from it to the most distant black cell (denoted by <span class=\"tex-span\"><i>D</i></span>). </span><span style=\"\" title=\"\">It is easy to see that we can construct a sequence of <span class=\"tex-span\"><i>D</i> + 1</span> repainting leads to the desired coloring:<br /><br /></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\"></span><span style=\"\" title=\"\">The first step of color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i></span> in black color</span></span><br /></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\">At the second step color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i> - 1</span> in white</span></span></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span title=\"\">Etc.</span></span></li></ul><span lang=\"en\"><span title=\"\"><br /></span><span style=\"\" title=\"\">Of all the cells, choose the one for which this distance is minimal, and this distance increased by one will be the answer to the problem.</span></span></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/37\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 37</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2424-798\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2424\",\n blogEntryId: \"798\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2337\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #37</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+32</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/vepifanov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/vepifanov\">\n vepifanov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/798#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/798#comments\">\n 6\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"808\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (6)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13074\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/t__nt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/134/avatar/2584a6760a294637.jpg'/> </a>\n <div><a href=\"/profile/t__nt\" title=\"Master t__nt\" class=\"rated-user user-orange\">t__nt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 06:52\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13074\" href=\"?#comment-13074\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13074\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"134\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13074\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In the tutorial of Problem E, the way to paint the cells is brilliant. Meanwhile finding the cell to minimize D is just to optimize the solution in this way.<div>But how to prove that this method you paint the cells is the best? Thank you very much.</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13074 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13074 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13074\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13093\" commentParentId=\"13074\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 16:55\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13093\" href=\"?#comment-13093\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13074\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13093\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13093\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13093\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><span lang=\"en\"><span style=\"\" title=\"\">The proof is in short looks like this:<br /><br /></span><span style=\"\" title=\"\">First, compress all vertices between which distance is equal to zero in one component (get graph of connected components).<br /></span><span style=\"\" title=\"\">Note that if we repaint some cell, it can be repainted and all its component, as a result coloring will not change.<br /><br /></span><span style=\"\" title=\"\">1) we can prove that any coloring can be reduced to a form such that each subsequent repainting is a subset of the previous one.<br /></span><span style=\"\" title=\"\">2) the last repainting will consist of exactly one vertex (possibly the whole monochromatic connected region of the original board).<br /><br /></span><span style=\"\" title=\"\">Therefore, one of the best answers will be of the form described in the review. </span><span style=\"\" title=\"\">If as the initial vertex, we take a cell, lying in the last repainting of the optimal sequence, the algorithm finds the solution not worse than optimal.</span></span><div style=\"\"><div style=\"display: none;\"><span><span>Прослушать</span></span></div><div style=\"display: none;\"><span><span>На латинице</span></span></div><br /></div></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13093 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13093 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13093\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13076\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/samshu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/5855/avatar/2016640288859ccd.jpg'/> </a>\n <div><a href=\"/profile/samshu\" title=\"Newbie samshu\" class=\"rated-user user-gray\">samshu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 09:47\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13076\" href=\"?#comment-13076\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13076\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"5855\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13076\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I tried to simulate exactly the algorithm described for Problem C, but it obviously times out since it requires a huge memory space. Can anybody tell me how do i optimize it? I've posted my solution here -<br />http://ideone.com/il8Do</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13076 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13076 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13076\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13077\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/DStepanenko\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/DStepanenko\" title=\"Expert DStepanenko\" class=\"rated-user user-blue\">DStepanenko</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:16\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13077\" href=\"?#comment-13077\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13077\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"309\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13077\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Хотелось бы чтобы отписались люди, сдавшие эту задачу и имеющие альтернативные решения.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13077 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13077 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13077\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13079\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:36\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13079\" href=\"?#comment-13079\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13079\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13079\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13079\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Well, my solution doesn't need any memory at all. Process the lengths of the words in increasing order and try to find lexicographically smallest word at each step. Suppose <i>s</i> is the last word written out, and its length is <i>k</i>. Then all strings that have length <i>k</i> and are lexicographically not larger than <i>s</i>, are 'bad' (each of them has a prefix that is already written out). So, to find out the <i>k</i>-prefix of the next word we need to increase <i>s</i> by 1 (as a binary number). Obviously, if <i>s</i> consists of 1's it's impossible, since we will get a word of length <i>k</i>+1. Now we need to find lexicographically smallest encoding of the next word. To do that, just add zeros to the increased value of <i>s</i>.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13079 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13079 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13079\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13095\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 17:10\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13095\" href=\"?#comment-13095\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13095\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13095\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">This is solution of problem C from tutorial: <br />http://ideone.com/lHtSZ</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13095 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13095 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n 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Lesson Timetable"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Lesson Timetable</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>When Petya has free from computer games time, he attends university classes. Every day the lessons on Petya’s faculty consist of two double classes. The floor where the lessons take place is a long corridor with <span class=\"tex-span\"><i>M</i></span> classrooms numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>M</i></span>, situated along it.</p><p>All the students of Petya’s year are divided into <span class=\"tex-span\"><i>N</i></span> groups. Petya has noticed recently that these groups’ timetable has the following peculiarity: the number of the classroom where the first lesson of a group takes place does not exceed the number of the classroom where the second lesson of this group takes place. </p><p>Once Petya decided to count the number of ways in which one can make a lesson timetable for all these groups. The timetable is a set of <span class=\"tex-span\">2<i>N</i></span> numbers: for each group the number of the rooms where the first and the second lessons take place. Unfortunately, he quickly lost the track of his calculations and decided to count only the timetables that satisfy the following conditions:</p><p>1) On the first lesson in classroom <span class=\"tex-span\"><i>i</i></span> exactly <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub></span> groups must be present.</p><p>2) In classroom <span class=\"tex-span\"><i>i</i></span> no more than <span class=\"tex-span\"><i>Y</i><sub class=\"lower-index\"><i>i</i></sub></span> groups may be placed.</p><p>Help Petya count the number of timetables satisfying all those conditionsю As there can be a lot of such timetables, output modulo <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup> + 7</span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains one integer <span class=\"tex-span\"><i>M</i></span> (<span class=\"tex-span\">1 ≤ <i>M</i> ≤ 100</span>) — the number of classrooms.</p><p>The second line contains <span class=\"tex-span\"><i>M</i></span> space-separated integers — <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">0 ≤ <i>X</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>) the amount of groups present in classroom <span class=\"tex-span\"><i>i</i></span> during the first lesson.</p><p>The third line contains <span class=\"tex-span\"><i>M</i></span> space-separated integers — <span class=\"tex-span\"><i>Y</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">0 ≤ <i>Y</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>) the maximal amount of groups that can be present in classroom <span class=\"tex-span\"><i>i</i></span> at the same time.</p><p>It is guaranteed that all the <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>Y</i><sub class=\"lower-index\"><i>i</i></sub></span>, and that the sum of all the <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub></span> is positive and does not exceed <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the single line output the answer to the problem modulo <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup> + 7</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>1 1 1<br/>1 2 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>36<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>1 1 1<br/>1 1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6<br/></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>In the second sample test the first and the second lessons of each group must take place in the same classroom, that’s why the timetables will only be different in the rearrangement of the classrooms’ numbers for each group, e.g. <span class=\"tex-span\">3! = 6</span>.</p></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"a0500f9eada23626b9f086d2c85cba65\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"9ca010b5bc88a84f6e5bf74687b257a83dd1ef91\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_2786a2a686e00578dd39809a4f34b128b56e84d3\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Lesson Timetable</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>When Petya has free from computer games time, he attends university classes. Every day the lessons on Petya’s faculty consist of two double classes. The floor where the lessons take place is a long corridor with <span class=\"tex-span\"><i>M</i></span> classrooms numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>M</i></span>, situated along it.</p><p>All the students of Petya’s year are divided into <span class=\"tex-span\"><i>N</i></span> groups. Petya has noticed recently that these groups’ timetable has the following peculiarity: the number of the classroom where the first lesson of a group takes place does not exceed the number of the classroom where the second lesson of this group takes place. </p><p>Once Petya decided to count the number of ways in which one can make a lesson timetable for all these groups. The timetable is a set of <span class=\"tex-span\">2<i>N</i></span> numbers: for each group the number of the rooms where the first and the second lessons take place. Unfortunately, he quickly lost the track of his calculations and decided to count only the timetables that satisfy the following conditions:</p><p>1) On the first lesson in classroom <span class=\"tex-span\"><i>i</i></span> exactly <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub></span> groups must be present.</p><p>2) In classroom <span class=\"tex-span\"><i>i</i></span> no more than <span class=\"tex-span\"><i>Y</i><sub class=\"lower-index\"><i>i</i></sub></span> groups may be placed.</p><p>Help Petya count the number of timetables satisfying all those conditionsю As there can be a lot of such timetables, output modulo <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup> + 7</span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains one integer <span class=\"tex-span\"><i>M</i></span> (<span class=\"tex-span\">1 ≤ <i>M</i> ≤ 100</span>) — the number of classrooms.</p><p>The second line contains <span class=\"tex-span\"><i>M</i></span> space-separated integers — <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">0 ≤ <i>X</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>) the amount of groups present in classroom <span class=\"tex-span\"><i>i</i></span> during the first lesson.</p><p>The third line contains <span class=\"tex-span\"><i>M</i></span> space-separated integers — <span class=\"tex-span\"><i>Y</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">0 ≤ <i>Y</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>) the maximal amount of groups that can be present in classroom <span class=\"tex-span\"><i>i</i></span> at the same time.</p><p>It is guaranteed that all the <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>Y</i><sub class=\"lower-index\"><i>i</i></sub></span>, and that the sum of all the <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub></span> is positive and does not exceed <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the single line output the answer to the problem modulo <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup> + 7</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />1 1 1<br />1 2 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>36<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />1 1 1<br />1 1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6<br /></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>In the second sample test the first and the second lessons of each group must take place in the same classroom, that’s why the 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:06</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='0ab0f791e5640a29e183082a8066264f'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a href=\"/blog/entry/121171\">An Interesting Tree Problem</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/.Danet\" title=\"Expert .Danet\" class=\"rated-user user-blue\">.Danet</a> →\r\n <a href=\"/blog/entry/121172\">[TLE on pretest1]</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/sszcdjr\" title=\"Master sszcdjr\" class=\"rated-user user-orange\">sszcdjr</a> →\r\n <a href=\"/blog/entry/119859\">Codeforces Round 896 (Div. 1, Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/119880\">It's Happening! Meta Hacker Cup 2023 Schedule</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/DaviddeGea1\" title=\"Expert DaviddeGea1\" class=\"rated-user user-blue\">DaviddeGea1</a> →\r\n <a href=\"/blog/entry/70917\">Number of ways of dividing an array into 2 parts such that sum of each part is > k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a> →\r\n <a href=\"/blog/entry/74245\">Questions and doubts regarding Aliens DP trick</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/cgy4ever\" title=\"International Grandmaster cgy4ever\" class=\"rated-user user-red\">cgy4ever</a> →\r\n <a href=\"/blog/entry/8192\">Codeforces Round #190 — Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/hocky\" title=\"Candidate Master hocky\" class=\"rated-user user-violet\">hocky</a> →\r\n <a href=\"/blog/entry/95323\">FBHC wuining uw Day? Incwease uw stacc size! (ㅅ´ ˘ `)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/liouzhou_101\" title=\"International Master liouzhou_101\" class=\"rated-user user-orange\">liouzhou_101</a> →\r\n <a href=\"/blog/entry/87598\">Editorial of Codeforces Round #700</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div 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title=\"Unrated, atcoder_official\" class=\"rated-user user-black\">atcoder_official</a> →\r\n <a href=\"/blog/entry/121120\">We will hold UNIQUE VISION Programming Contest 2023 Autumn(AtCoder Beginner Contest 323)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/YouStill_DontKnowMeYet\" title=\"Candidate Master YouStill_DontKnowMeYet\" class=\"rated-user user-violet\">YouStill_DontKnowMeYet</a> →\r\n <a href=\"/blog/entry/117659\">[GYM] Al-Baath Collegiate Programming Contest 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/ankancool\" title=\"Expert ankancool\" class=\"rated-user user-blue\">ankancool</a> →\r\n <a href=\"/blog/entry/121136\">Invitation to AstroByte 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/GeZhiyuan\" title=\"Grandmaster GeZhiyuan\" class=\"rated-user user-red\">GeZhiyuan</a> →\r\n <a href=\"/blog/entry/120943\">Codeforces Round 901 (Div. 1, Div. 2) Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a> →\r\n <a href=\"/blog/entry/120772\">PSA: Increase your stack size before the Meta Hacker Cup, here's how</a>\r\n <img alt=\"New 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title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bn00b\" title=\"Newbie Bn00b\" class=\"rated-user user-gray\">Bn00b</a> →\r\n <a href=\"/blog/entry/98820\">[FEATURE REQUEST : ATCODER] TOPICS TAGS AND SORTING BY SOLVE COUNT</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a> →\r\n <a href=\"/blog/entry/121163\">AtCoder Regular Contest 166 Announcement</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/windva\" title=\"Grandmaster windva\" class=\"rated-user user-red\">windva</a> →\r\n <a href=\"/blog/entry/120644\">Codeforces Round 899 (Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Misa-Misa\" title=\"Expert Misa-Misa\" class=\"rated-user user-blue\">Misa-Misa</a> →\r\n <a href=\"/blog/entry/121157\">Someone please help me understand this.</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/shivam565\" title=\"Specialist shivam565\" class=\"rated-user user-cyan\">shivam565</a> →\r\n <a href=\"/blog/entry/108348\">Total number of subarrays with sum atmost k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n </ul>\r\n </div>\r\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/recent-actions\">Detailed →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n</div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li><a\r\n href=\"/profile/vepifanov\">vepifanov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/vepifanov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/vepifanov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/vepifanov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/vepifanov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/vepifanov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/vepifanov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/vepifanov\" style=\"text-decoration:none;color:black !important;\">vepifanov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"798\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/798\"> Codeforces Beta Round #37 (Tutorial)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a>,\r\n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><b>A. Towers</b><br /> <span lang=\"en\"><span style=\"color: rgb(0,0,0);\" title=\"\">The total number of towers is equal to number of different numbers in this set. </span><span style=\"\" title=\"\">To get the maximum height of the tower, it was possible to calculate for each length the number of bars with this length, and from these numbers is to choose the maximum.</span></span><br /> <br /> <b>B. Computer Game</b><br /> <span lang=\"en\"><span title=\"\">Constraints in the problem allows us to solve it this way: we keep the current number of health from the boss, and current summary damage from used scrolls per second. </span><span style=\"\" title=\"\">At the next step, we choose which scrolls we can use in the current second. </span><span style=\"\" title=\"\">Of all these, we find the scroll, which causes the most damage, and apply it. </span><span style=\"\" title=\"\">If at some point we could not use any of the scrolls, and the current damage in one second does not exceed regeneration, we deduce that there are no answers. </span><span style=\"\" title=\"\">Otherwise, continue to iterate the algorithm until the number hit points will be nonnegative.</span></span><br /> <br /> <b>C. Old Berland Language</b><br /><span lang=\"en\"><span style=\"\" title=\"\">One of the easiest to understand solutions of this problem is as follows: sort the words in ascending order of length, while remembering their positions in the source list. </span><span style=\"\" title=\"\">We will consistently build our set, starting with the short strings: strings of length one can only be strings "0" and "1". </span><span style=\"\" title=\"\">If the number of words of length one in a set are more than two, hence there are no answers. </span><span style=\"\" title=\"\">Add the desired number of strings of length one to answer, and remove it from the current list. </span><span style=\"\" title=\"\">Then look at the string of length two: each of the remaining strings of length one can be extended in two ways (having added to each of these symbols 0 and 1). </span><span style=\"\" title=\"\">Add the desired number of strings of length two in our answer, and then increase the length of the remaining strings by one.</span><span style=\"\" title=\"\"> Continue this process, </span></span><span lang=\"en\"><span style=\"\" title=\"\">until we get all words from the input set</span></span><span lang=\"en\"><span style=\"\" title=\"\">. </span><span style=\"\" title=\"\">You can see that if at some moment the number of allowable words exceeded the number of remaining, the extra words can be ignored and solution takes </span></span><span lang=\"en\"><span style=\"\" title=\"\">O (N * the maximum length of input set) time.</span></span> <br /></p> <p><b>D. Lesson Timetable<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">This problem is solved by dynamic programming:<br /><br /></span><span style=\"\" title=\"\">state of dynamics will be a pair of numbers - the number of current room and number of groups which have first lesson in the room with a number not exceeding the current and for which the second room is not defined yet. </span><span style=\"\" title=\"\">For each state check all possible number of groups for which the second lesson will be held in the current classroom. </span><span style=\"\" title=\"\">When you add an answer from the new state, it must be multiplied by the corresponding binomial coefficients (the number of ways to select groups which have the first lesson in next room - <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub> + 1</span>, and the number of ways to select groups which have the second lesson</span></span><span lang=\"en\"><span style=\"\" title=\"\"> in the current classroom).</span></span><p> </p> <p><b>E. Trial for Chief<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">First, we construct the following graph: each cell we associate a vertex of the same color as the cell itself. </span><span style=\"\" title=\"\">Between neighboring cells hold an edge of weight 0, if the cells share the same color and weight of 1, if different. </span><span style=\"\" title=\"\">Now, for each cell count the shortest distance from it to the most distant black cell (denoted by <span class=\"tex-span\"><i>D</i></span>). </span><span style=\"\" title=\"\">It is easy to see that we can construct a sequence of <span class=\"tex-span\"><i>D</i> + 1</span> repainting leads to the desired coloring:<br /><br /></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\"></span><span style=\"\" title=\"\">The first step of color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i></span> in black color</span></span><br /></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\">At the second step color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i> - 1</span> in white</span></span></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span title=\"\">Etc.</span></span></li></ul><span lang=\"en\"><span title=\"\"><br /></span><span style=\"\" title=\"\">Of all the cells, choose the one for which this distance is minimal, and this distance increased by one will be the answer to the problem.</span></span></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/37\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 37</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2424-798\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2424\",\n blogEntryId: \"798\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2337\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #37</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+32</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/vepifanov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/vepifanov\">\n vepifanov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/798#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/798#comments\">\n 6\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"808\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (6)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13074\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/t__nt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/134/avatar/2584a6760a294637.jpg'/> </a>\n <div><a href=\"/profile/t__nt\" title=\"Master t__nt\" class=\"rated-user user-orange\">t__nt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 06:52\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13074\" href=\"?#comment-13074\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13074\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"134\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13074\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In the tutorial of Problem E, the way to paint the cells is brilliant. Meanwhile finding the cell to minimize D is just to optimize the solution in this way.<div>But how to prove that this method you paint the cells is the best? Thank you very much.</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13074 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13074 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13074\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13093\" commentParentId=\"13074\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 16:55\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13093\" href=\"?#comment-13093\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13074\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13093\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13093\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13093\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><span lang=\"en\"><span style=\"\" title=\"\">The proof is in short looks like this:<br /><br /></span><span style=\"\" title=\"\">First, compress all vertices between which distance is equal to zero in one component (get graph of connected components).<br /></span><span style=\"\" title=\"\">Note that if we repaint some cell, it can be repainted and all its component, as a result coloring will not change.<br /><br /></span><span style=\"\" title=\"\">1) we can prove that any coloring can be reduced to a form such that each subsequent repainting is a subset of the previous one.<br /></span><span style=\"\" title=\"\">2) the last repainting will consist of exactly one vertex (possibly the whole monochromatic connected region of the original board).<br /><br /></span><span style=\"\" title=\"\">Therefore, one of the best answers will be of the form described in the review. </span><span style=\"\" title=\"\">If as the initial vertex, we take a cell, lying in the last repainting of the optimal sequence, the algorithm finds the solution not worse than optimal.</span></span><div style=\"\"><div style=\"display: none;\"><span><span>Прослушать</span></span></div><div style=\"display: none;\"><span><span>На латинице</span></span></div><br /></div></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13093 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13093 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13093\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13076\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/samshu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/5855/avatar/2016640288859ccd.jpg'/> </a>\n <div><a href=\"/profile/samshu\" title=\"Newbie samshu\" class=\"rated-user user-gray\">samshu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 09:47\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13076\" href=\"?#comment-13076\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13076\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"5855\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13076\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I tried to simulate exactly the algorithm described for Problem C, but it obviously times out since it requires a huge memory space. Can anybody tell me how do i optimize it? I've posted my solution here -<br />http://ideone.com/il8Do</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13076 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13076 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13076\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13077\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/DStepanenko\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/DStepanenko\" title=\"Expert DStepanenko\" class=\"rated-user user-blue\">DStepanenko</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:16\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13077\" href=\"?#comment-13077\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13077\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"309\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13077\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Хотелось бы чтобы отписались люди, сдавшие эту задачу и имеющие альтернативные решения.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13077 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13077 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13077\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13079\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:36\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13079\" href=\"?#comment-13079\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13079\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13079\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13079\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Well, my solution doesn't need any memory at all. Process the lengths of the words in increasing order and try to find lexicographically smallest word at each step. Suppose <i>s</i> is the last word written out, and its length is <i>k</i>. Then all strings that have length <i>k</i> and are lexicographically not larger than <i>s</i>, are 'bad' (each of them has a prefix that is already written out). So, to find out the <i>k</i>-prefix of the next word we need to increase <i>s</i> by 1 (as a binary number). Obviously, if <i>s</i> consists of 1's it's impossible, since we will get a word of length <i>k</i>+1. Now we need to find lexicographically smallest encoding of the next word. To do that, just add zeros to the increased value of <i>s</i>.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13079 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13079 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13079\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13095\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 17:10\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13095\" href=\"?#comment-13095\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13095\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13095\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">This is solution of problem C from tutorial: <br />http://ideone.com/lHtSZ</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13095 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13095 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n 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Trial for Chief"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Trial for Chief</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Having unraveled the Berland Dictionary, the scientists managed to read the notes of the chroniclers of that time. For example, they learned how the chief of the ancient Berland tribe was chosen.</p><p>As soon as enough pretenders was picked, the following test took place among them: the chief of the tribe took a slab divided by horizontal and vertical stripes into identical squares (the slab consisted of <span class=\"tex-span\"><i>N</i></span> lines and <span class=\"tex-span\"><i>M</i></span> columns) and painted every square black or white. Then every pretender was given a slab of the same size but painted entirely white. Within a day a pretender could paint any side-linked set of the squares of the slab some color. The set is called linked if for any two squares belonging to the set there is a path belonging the set on which any two neighboring squares share a side. The aim of each pretender is to paint his slab in the exactly the same way as the chief’s slab is painted. The one who paints a slab like that first becomes the new chief.</p><p>Scientists found the slab painted by the ancient Berland tribe chief. Help them to determine the minimal amount of days needed to find a new chief if he had to paint his slab in the given way.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two integers <span class=\"tex-span\"><i>N</i></span> and <span class=\"tex-span\"><i>M</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i>, <i>M</i> ≤ 50</span>) — the number of lines and columns on the slab. The next <span class=\"tex-span\"><i>N</i></span> lines contain <span class=\"tex-span\"><i>M</i></span> symbols each — the final coloration of the slab. <span class=\"tex-span\"><i>W</i></span> stands for the square that should be painted white and <span class=\"tex-span\"><i>B</i></span> — for the square that should be painted black.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the single line output the minimal number of repaintings of side-linked areas needed to get the required coloration of the slab.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br/>WBW<br/>BWB<br/>WBW<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 3<br/>BBB<br/>BWB<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"0aa140172e44edad1c329f942b62fd37\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"9ca010b5bc88a84f6e5bf74687b257a83dd1ef91\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/37\">Codeforces Beta Round 37</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"E\" data-uuid=\"ps_866bf43c8fd03c9cfb8bdd9adb4d7bd0a6475e91\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Trial for Chief</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Having unraveled the Berland Dictionary, the scientists managed to read the notes of the chroniclers of that time. For example, they learned how the chief of the ancient Berland tribe was chosen.</p><p>As soon as enough pretenders was picked, the following test took place among them: the chief of the tribe took a slab divided by horizontal and vertical stripes into identical squares (the slab consisted of <span class=\"tex-span\"><i>N</i></span> lines and <span class=\"tex-span\"><i>M</i></span> columns) and painted every square black or white. Then every pretender was given a slab of the same size but painted entirely white. Within a day a pretender could paint any side-linked set of the squares of the slab some color. The set is called linked if for any two squares belonging to the set there is a path belonging the set on which any two neighboring squares share a side. The aim of each pretender is to paint his slab in the exactly the same way as the chief’s slab is painted. The one who paints a slab like that first becomes the new chief.</p><p>Scientists found the slab painted by the ancient Berland tribe chief. Help them to determine the minimal amount of days needed to find a new chief if he had to paint his slab in the given way.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two integers <span class=\"tex-span\"><i>N</i></span> and <span class=\"tex-span\"><i>M</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i>, <i>M</i> ≤ 50</span>) — the number of lines and columns on the slab. The next <span class=\"tex-span\"><i>N</i></span> lines contain <span class=\"tex-span\"><i>M</i></span> symbols each — the final coloration of the slab. <span class=\"tex-span\"><i>W</i></span> stands for the square that should be painted white and <span class=\"tex-span\"><i>B</i></span> — for the square that should be painted black.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the single line output the minimal number of repaintings of side-linked areas needed to get the required coloration of the slab.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br />WBW<br />BWB<br />WBW<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 3<br />BBB<br />BWB<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=E]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if (result[\"success\"] === \"true\") {\r\n Codeforces.facebox(\".diff-popup\", 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:06</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='0ab0f791e5640a29e183082a8066264f'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/vepifanov\">vepifanov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/vepifanov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/vepifanov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/vepifanov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/vepifanov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/vepifanov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/vepifanov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/vepifanov\" style=\"text-decoration:none;color:black !important;\">vepifanov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"798\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/798\"> Codeforces Beta Round #37 (Tutorial)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a>,\r\n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><b>A. Towers</b><br /> <span lang=\"en\"><span style=\"color: rgb(0,0,0);\" title=\"\">The total number of towers is equal to number of different numbers in this set. </span><span style=\"\" title=\"\">To get the maximum height of the tower, it was possible to calculate for each length the number of bars with this length, and from these numbers is to choose the maximum.</span></span><br /> <br /> <b>B. Computer Game</b><br /> <span lang=\"en\"><span title=\"\">Constraints in the problem allows us to solve it this way: we keep the current number of health from the boss, and current summary damage from used scrolls per second. </span><span style=\"\" title=\"\">At the next step, we choose which scrolls we can use in the current second. </span><span style=\"\" title=\"\">Of all these, we find the scroll, which causes the most damage, and apply it. </span><span style=\"\" title=\"\">If at some point we could not use any of the scrolls, and the current damage in one second does not exceed regeneration, we deduce that there are no answers. </span><span style=\"\" title=\"\">Otherwise, continue to iterate the algorithm until the number hit points will be nonnegative.</span></span><br /> <br /> <b>C. Old Berland Language</b><br /><span lang=\"en\"><span style=\"\" title=\"\">One of the easiest to understand solutions of this problem is as follows: sort the words in ascending order of length, while remembering their positions in the source list. </span><span style=\"\" title=\"\">We will consistently build our set, starting with the short strings: strings of length one can only be strings "0" and "1". </span><span style=\"\" title=\"\">If the number of words of length one in a set are more than two, hence there are no answers. </span><span style=\"\" title=\"\">Add the desired number of strings of length one to answer, and remove it from the current list. </span><span style=\"\" title=\"\">Then look at the string of length two: each of the remaining strings of length one can be extended in two ways (having added to each of these symbols 0 and 1). </span><span style=\"\" title=\"\">Add the desired number of strings of length two in our answer, and then increase the length of the remaining strings by one.</span><span style=\"\" title=\"\"> Continue this process, </span></span><span lang=\"en\"><span style=\"\" title=\"\">until we get all words from the input set</span></span><span lang=\"en\"><span style=\"\" title=\"\">. </span><span style=\"\" title=\"\">You can see that if at some moment the number of allowable words exceeded the number of remaining, the extra words can be ignored and solution takes </span></span><span lang=\"en\"><span style=\"\" title=\"\">O (N * the maximum length of input set) time.</span></span> <br /></p> <p><b>D. Lesson Timetable<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">This problem is solved by dynamic programming:<br /><br /></span><span style=\"\" title=\"\">state of dynamics will be a pair of numbers - the number of current room and number of groups which have first lesson in the room with a number not exceeding the current and for which the second room is not defined yet. </span><span style=\"\" title=\"\">For each state check all possible number of groups for which the second lesson will be held in the current classroom. </span><span style=\"\" title=\"\">When you add an answer from the new state, it must be multiplied by the corresponding binomial coefficients (the number of ways to select groups which have the first lesson in next room - <span class=\"tex-span\"><i>X</i><sub class=\"lower-index\"><i>i</i></sub> + 1</span>, and the number of ways to select groups which have the second lesson</span></span><span lang=\"en\"><span style=\"\" title=\"\"> in the current classroom).</span></span><p> </p> <p><b>E. Trial for Chief<br /></b></p><span lang=\"en\"><span style=\"\" title=\"\">First, we construct the following graph: each cell we associate a vertex of the same color as the cell itself. </span><span style=\"\" title=\"\">Between neighboring cells hold an edge of weight 0, if the cells share the same color and weight of 1, if different. </span><span style=\"\" title=\"\">Now, for each cell count the shortest distance from it to the most distant black cell (denoted by <span class=\"tex-span\"><i>D</i></span>). </span><span style=\"\" title=\"\">It is easy to see that we can construct a sequence of <span class=\"tex-span\"><i>D</i> + 1</span> repainting leads to the desired coloring:<br /><br /></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\"></span><span style=\"\" title=\"\">The first step of color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i></span> in black color</span></span><br /></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span style=\"\" title=\"\">At the second step color all the cells at a distance less than or equal to <span class=\"tex-span\"><i>D</i> - 1</span> in white</span></span></li></ul><span lang=\"en\"><span style=\"\" title=\"\"></span></span><ul><li><span lang=\"en\"><span title=\"\">Etc.</span></span></li></ul><span lang=\"en\"><span title=\"\"><br /></span><span style=\"\" title=\"\">Of all the cells, choose the one for which this distance is minimal, and this distance increased by one will be the answer to the problem.</span></span></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/37\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 37</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2424-798\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2424\",\n blogEntryId: \"798\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2337\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #37</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+32</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-798\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/vepifanov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/vepifanov\">\n vepifanov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/27/2010 17:52\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/798#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/798#comments\">\n 6\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"808\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (6)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13074\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/t__nt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/134/avatar/2584a6760a294637.jpg'/> </a>\n <div><a href=\"/profile/t__nt\" title=\"Master t__nt\" class=\"rated-user user-orange\">t__nt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 06:52\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13074\" href=\"?#comment-13074\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13074\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"134\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13074\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In the tutorial of Problem E, the way to paint the cells is brilliant. Meanwhile finding the cell to minimize D is just to optimize the solution in this way.<div>But how to prove that this method you paint the cells is the best? Thank you very much.</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13074 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13074 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13074\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13093\" commentParentId=\"13074\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 16:55\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13093\" href=\"?#comment-13093\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13074\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13093\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13093\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13093\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><span lang=\"en\"><span style=\"\" title=\"\">The proof is in short looks like this:<br /><br /></span><span style=\"\" title=\"\">First, compress all vertices between which distance is equal to zero in one component (get graph of connected components).<br /></span><span style=\"\" title=\"\">Note that if we repaint some cell, it can be repainted and all its component, as a result coloring will not change.<br /><br /></span><span style=\"\" title=\"\">1) we can prove that any coloring can be reduced to a form such that each subsequent repainting is a subset of the previous one.<br /></span><span style=\"\" title=\"\">2) the last repainting will consist of exactly one vertex (possibly the whole monochromatic connected region of the original board).<br /><br /></span><span style=\"\" title=\"\">Therefore, one of the best answers will be of the form described in the review. </span><span style=\"\" title=\"\">If as the initial vertex, we take a cell, lying in the last repainting of the optimal sequence, the algorithm finds the solution not worse than optimal.</span></span><div style=\"\"><div style=\"display: none;\"><span><span>Прослушать</span></span></div><div style=\"display: none;\"><span><span>На латинице</span></span></div><br /></div></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13093 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13093 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13093\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13076\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/samshu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/5855/avatar/2016640288859ccd.jpg'/> </a>\n <div><a href=\"/profile/samshu\" title=\"Newbie samshu\" class=\"rated-user user-gray\">samshu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 09:47\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13076\" href=\"?#comment-13076\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13076\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"5855\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13076\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I tried to simulate exactly the algorithm described for Problem C, but it obviously times out since it requires a huge memory space. Can anybody tell me how do i optimize it? I've posted my solution here -<br />http://ideone.com/il8Do</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13076 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13076 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13076\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13077\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/DStepanenko\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/DStepanenko\" title=\"Expert DStepanenko\" class=\"rated-user user-blue\">DStepanenko</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:16\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13077\" href=\"?#comment-13077\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13077\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"309\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13077\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Хотелось бы чтобы отписались люди, сдавшие эту задачу и имеющие альтернативные решения.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13077 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13077 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13077\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13079\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 10:36\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13079\" href=\"?#comment-13079\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"13079\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"13079\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13079\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Well, my solution doesn't need any memory at all. Process the lengths of the words in increasing order and try to find lexicographically smallest word at each step. Suppose <i>s</i> is the last word written out, and its length is <i>k</i>. Then all strings that have length <i>k</i> and are lexicographically not larger than <i>s</i>, are 'bad' (each of them has a prefix that is already written out). So, to find out the <i>k</i>-prefix of the next word we need to increase <i>s</i> by 1 (as a binary number). Obviously, if <i>s</i> consists of 1's it's impossible, since we will get a word of length <i>k</i>+1. Now we need to find lexicographically smallest encoding of the next word. To do that, just add zeros to the increased value of <i>s</i>.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13079 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13079 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13079\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13095\" commentParentId=\"13076\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/vepifanov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/><img title='Badge of honor for supporting Codeforces on its 10th anniversary' src='//codeforces.org/s/81027/images/if_medal-bronze-blue_46108.png' style='position:absolute;bottom:5px;right:10px'/> </a>\n <div><a href=\"/profile/vepifanov\" title=\"International Grandmaster vepifanov\" class=\"rated-user user-red\">vepifanov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 17:10\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13095\" href=\"?#comment-13095\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13076\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13095\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"500\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13095\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">This is solution of problem C from tutorial: <br />http://ideone.com/lHtSZ</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13095 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13095 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n 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Army"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Army</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The Berland Armed Forces System consists of <span class=\"tex-span\"><i>n</i></span> ranks that are numbered using natural numbers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>, where <span class=\"tex-span\">1</span> is the lowest rank and <span class=\"tex-span\"><i>n</i></span> is the highest rank.</p><p>One needs exactly <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span> years to rise from rank <span class=\"tex-span\"><i>i</i></span> to rank <span class=\"tex-span\"><i>i</i> + 1</span>. Reaching a certain rank <span class=\"tex-span\"><i>i</i></span> having not reached all the previous <span class=\"tex-span\"><i>i</i> - 1</span> ranks is impossible.</p><p>Vasya has just reached a new rank of <span class=\"tex-span\"><i>a</i></span>, but he dreams of holding the rank of <span class=\"tex-span\"><i>b</i></span>. Find for how many more years Vasya should serve in the army until he can finally realize his dream.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">2 ≤ <i>n</i> ≤ 100</span>). The second line contains <span class=\"tex-span\"><i>n</i> - 1</span> integers <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>d</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>). The third input line contains two integers <span class=\"tex-span\"><i>a</i></span> and <span class=\"tex-span\"><i>b</i></span> (<span class=\"tex-span\">1 ≤ <i>a</i> < <i>b</i> ≤ <i>n</i></span>). The numbers on the lines are space-separated.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the single number which is the number of years that Vasya needs to rise from rank <span class=\"tex-span\"><i>a</i></span> to rank <span class=\"tex-span\"><i>b</i></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>5 6<br/>1 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>5 6<br/>1 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>11<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"788f4d7dda2c52f53a489cb7f5fdc088\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"fbd794f7652711d83dbb2390881fc29f4cda1cfe\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/38\">School Personal Contest #1 (Winter Computer School 2010/11) - Codeforces Beta Round 38 (ACM-ICPC Rules)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='788f4d7dda2c52f53a489cb7f5fdc088'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/38/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *800\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='788f4d7dda2c52f53a489cb7f5fdc088'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"190\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='788f4d7dda2c52f53a489cb7f5fdc088'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"190\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/800\" title=\"School Individual Contest #1 (WCS 2010/11) - Codeforces Beta Round #38 (ACM-ICPC Rules)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"158:159\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/812\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"776\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/815\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"777\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/816\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\" target=\"_blank\">Tutorial #3 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"778\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/805\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\" target=\"_blank\">Tutorial #4 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"772\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/806\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\" target=\"_blank\">Tutorial #5 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"773\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/807\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\" target=\"_blank\">Tutorial #6 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"774\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/808\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи D)\" target=\"_blank\">Tutorial #7 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"775\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи D)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/38\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/38/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/38/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/38/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/38/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/38/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_c70cfcfae1ed6f800fd6847c566dc1d68d0ce31a\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Army</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The Berland Armed Forces System consists of <span class=\"tex-span\"><i>n</i></span> ranks that are numbered using natural numbers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>, where <span class=\"tex-span\">1</span> is the lowest rank and <span class=\"tex-span\"><i>n</i></span> is the highest rank.</p><p>One needs exactly <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span> years to rise from rank <span class=\"tex-span\"><i>i</i></span> to rank <span class=\"tex-span\"><i>i</i> + 1</span>. Reaching a certain rank <span class=\"tex-span\"><i>i</i></span> having not reached all the previous <span class=\"tex-span\"><i>i</i> - 1</span> ranks is impossible.</p><p>Vasya has just reached a new rank of <span class=\"tex-span\"><i>a</i></span>, but he dreams of holding the rank of <span class=\"tex-span\"><i>b</i></span>. Find for how many more years Vasya should serve in the army until he can finally realize his dream.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">2 ≤ <i>n</i> ≤ 100</span>). The second line contains <span class=\"tex-span\"><i>n</i> - 1</span> integers <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>d</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>). The third input line contains two integers <span class=\"tex-span\"><i>a</i></span> and <span class=\"tex-span\"><i>b</i></span> (<span class=\"tex-span\">1 ≤ <i>a</i> < <i>b</i> ≤ <i>n</i></span>). The numbers on the lines are space-separated.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the single number which is the number of years that Vasya needs to rise from rank <span class=\"tex-span\"><i>a</i></span> to rank <span class=\"tex-span\"><i>b</i></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />5 6<br />1 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />5 6<br />1 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>11<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=A]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span 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(Разбор задачи C)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/NALP\" title=\"Master NALP\" class=\"rated-user user-orange\">NALP</a>,\r\n <span class=\"format-humantime\" title=\"Oct/31/2010 19:40\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h1>Задача C. "Жалюзи"</h1>Нетрудно понять, что для некоторой фиксированной длины полос жалюзи <span class=\"tex-span\"><i>x</i></span>, максимальное количество полос, которые можно получить, равно: <br /><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/6408b359e53178405bfb4756205554134b7fb4bb.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><br /><br />тогда переберем это значение <span class=\"tex-span\"><i>x</i> ≥ <i>l</i></span>, и найдем максимум выражения <span class=\"tex-span\"><i>x</i>· <i>f</i>(<i>x</i>)</span>. Это число и надо вывести.</div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-3-812\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"3\",\n blogEntryId: \"812\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80\" class=\"tag notice\" 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Chess"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Chess</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Two chess pieces, a rook and a knight, stand on a standard chessboard <span class=\"tex-span\">8 × 8</span> in size. The positions in which they are situated are known. It is guaranteed that none of them beats the other one.</p><p>Your task is to find the number of ways to place another knight on the board so that none of the three pieces on the board beat another one. A new piece can only be placed on an empty square.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains the description of the rook's position on the board. This description is a line which is 2 in length. Its first symbol is a lower-case Latin letter from <span class=\"tex-font-style-tt\">a</span> to <span class=\"tex-font-style-tt\">h</span>, and its second symbol is a number from 1 to 8. The second line contains the description of the knight's position in a similar way. It is guaranteed that their positions do not coincide.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number which is the required number of ways.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>a1<br/>b2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>44<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>a8<br/>d4<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>38<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"b6e11aba1a2bc9db0cbb088c7d1b6ff7\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"fbd794f7652711d83dbb2390881fc29f4cda1cfe\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/38\">School Personal Contest #1 (Winter Computer School 2010/11) - Codeforces Beta Round 38 (ACM-ICPC Rules)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='b6e11aba1a2bc9db0cbb088c7d1b6ff7'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/38/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Brute force\">\r\n brute force\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Mathematics including integration, differential equations, etc\">\r\n math\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1200\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='b6e11aba1a2bc9db0cbb088c7d1b6ff7'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"191\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='b6e11aba1a2bc9db0cbb088c7d1b6ff7'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"191\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/800\" title=\"School Individual Contest #1 (WCS 2010/11) - Codeforces Beta Round #38 (ACM-ICPC Rules)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"158:159\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/812\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"776\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/815\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"777\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. 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Chess</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Two chess pieces, a rook and a knight, stand on a standard chessboard <span class=\"tex-span\">8 × 8</span> in size. The positions in which they are situated are known. It is guaranteed that none of them beats the other one.</p><p>Your task is to find the number of ways to place another knight on the board so that none of the three pieces on the board beat another one. A new piece can only be placed on an empty square.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains the description of the rook's position on the board. This description is a line which is 2 in length. Its first symbol is a lower-case Latin letter from <span class=\"tex-font-style-tt\">a</span> to <span class=\"tex-font-style-tt\">h</span>, and its second symbol is a number from 1 to 8. The second line contains the description of the knight's position in a similar way. It is guaranteed that their positions do not coincide.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number which is the required number of ways.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>a1<br />b2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>44<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>a8<br />d4<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>38<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=B]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:05</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a 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(Разбор задачи C)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/NALP\" title=\"Master NALP\" class=\"rated-user user-orange\">NALP</a>,\r\n <span class=\"format-humantime\" title=\"Oct/31/2010 19:40\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h1>Задача C. "Жалюзи"</h1>Нетрудно понять, что для некоторой фиксированной длины полос жалюзи <span class=\"tex-span\"><i>x</i></span>, максимальное количество полос, которые можно получить, равно: <br /><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/6408b359e53178405bfb4756205554134b7fb4bb.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><br /><br />тогда переберем это значение <span class=\"tex-span\"><i>x</i> ≥ <i>l</i></span>, и найдем максимум выражения <span class=\"tex-span\"><i>x</i>· <i>f</i>(<i>x</i>)</span>. Это число и надо вывести.</div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-3-812\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"3\",\n blogEntryId: \"812\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80\" class=\"tag notice\" style=\"text-decoration: none;\">разбор</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-812\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:gray'>0</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-812\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/NALP\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/NALP\">\n NALP\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/31/2010 19:40\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/812#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/812#comments\">\n 0\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"822\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (0)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n <br/>\r\n\r\n<div id=\"editBox-822\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 0.5em;left:4px;display: none;\">\r\n <input type=\"radio\" name=\"locale\" value=\"en\"><span style=\"font-size: 1.2rem;position: relative; bottom: 3px;\">In English</span>\r\n <input style=\"margin-left:1em\" type=\"radio\" name=\"locale\" value=\"ru\"><span style=\"font-size: 1.2rem;position: relative; bottom: 3px;\">In Russian</span>\r\n </div>\r\n <textarea data-drafts-id=\"CommentReplyFrame\" class=\"wysiwyg\" 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return false;\r\n });\r\n $(\".topic-vote-down-812\").click(function () {\r\n $.post(\"/data/topic/vote\", {topicId: 812, _tta: Codeforces.tta(), topicRevisionId: 2722, vote: -1}, function(data) {\r\n Codeforces.showMessage(data);\r\n adjustTopicComplainFrames();\r\n }, \"json\");\r\n return false;\r\n });\r\n });\n </script>\n</div>\r\n </div>\r\n </div>\r\n </div>\n </div>\n <br style=\"clear: both;\"/>\n <div id=\"footer\">\n <div><a href=\"https://codeforces.com/\">Codeforces</a> (c) Copyright 2010-2023 Mike Mirzayanov</div>\n <div>The only programming contests Web 2.0 platform</div>\n <div>Server time: <span class=\"format-timewithseconds\" data-locale=\"en\">Oct/07/2023 22:07:55</span> (h1).</div>\n <div>Desktop version, switch to <a rel=\"nofollow\" class=\"switchToMobile\" href=\"?mobile=true\">mobile version</a>.</div>\n <div class=\"smaller\"><a href=\"/privacy\">Privacy Policy</a></div>\n\n <div style=\"margin-top: 25px;\">\n Supported by\n </div>\n <div style=\"margin-top: 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Blinds"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Blinds</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The blinds are known to consist of opaque horizontal stripes that can be rotated thus regulating the amount of light flowing in the room. There are <span class=\"tex-span\"><i>n</i></span> blind stripes with the width of 1 in the factory warehouse for blind production. The problem is that all of them are spare details from different orders, that is, they may not have the same length (it is even possible for them to have different lengths)</p><p>Every stripe can be cut into two or more parts. The cuttings are made perpendicularly to the side along which the length is measured. Thus the cuttings do not change the width of a stripe but each of the resulting pieces has a lesser length (the sum of which is equal to the length of the initial stripe)</p><p>After all the cuttings the blinds are constructed through consecutive joining of several parts, similar in length, along sides, along which length is measured. Also, apart from the resulting pieces an initial stripe can be used as a blind if it hasn't been cut. It is forbidden to construct blinds in any other way.</p><p>Thus, if the blinds consist of <span class=\"tex-span\"><i>k</i></span> pieces each <span class=\"tex-span\"><i>d</i></span> in length, then they are of form of a rectangle of <span class=\"tex-span\"><i>k</i> × <i>d</i></span> bourlemeters. </p><p>Your task is to find for what window possessing the largest possible area the blinds can be made from the given stripes if on technical grounds it is forbidden to use pieces shorter than <span class=\"tex-span\"><i>l</i></span> bourlemeter. The window is of form of a rectangle with side lengths as positive integers.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first output line contains two space-separated integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>l</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>l</i> ≤ 100</span>). They are the number of stripes in the warehouse and the minimal acceptable length of a blind stripe in bourlemeters. The second line contains space-separated <span class=\"tex-span\"><i>n</i></span> integers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span>. They are the lengths of initial stripes in bourlemeters (<span class=\"tex-span\">1 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the single number — the maximal area of the window in square bourlemeters that can be completely covered. If no window with a positive area that can be covered completely without breaking any of the given rules exist, then print the single number <span class=\"tex-span\">0</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4 2<br/>1 2 3 4<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>8<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5 3<br/>5 5 7 3 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>15<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 3<br/>1 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0<br/></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>In the first sample test the required window is <span class=\"tex-span\">2 × 4</span> in size and the blinds for it consist of 4 parts, each 2 bourlemeters long. One of the parts is the initial stripe with the length of 2, the other one is a part of a cut stripe with the length of 3 and the two remaining stripes are parts of a stripe with the length of 4 cut in halves.</p></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"5c11bbb359042577fd1f7658acdfba2f\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"fbd794f7652711d83dbb2390881fc29f4cda1cfe\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/38\">School Personal Contest #1 (Winter Computer School 2010/11) - Codeforces Beta Round 38 (ACM-ICPC Rules)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='5c11bbb359042577fd1f7658acdfba2f'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/38/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Brute force\">\r\n brute force\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1400\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='5c11bbb359042577fd1f7658acdfba2f'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"192\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='5c11bbb359042577fd1f7658acdfba2f'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"192\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/800\" title=\"School Individual Contest #1 (WCS 2010/11) - Codeforces Beta Round #38 (ACM-ICPC Rules)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"158:159\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/812\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"776\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/815\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"777\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/816\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\" target=\"_blank\">Tutorial #3 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"778\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. 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Blinds</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The blinds are known to consist of opaque horizontal stripes that can be rotated thus regulating the amount of light flowing in the room. There are <span class=\"tex-span\"><i>n</i></span> blind stripes with the width of 1 in the factory warehouse for blind production. The problem is that all of them are spare details from different orders, that is, they may not have the same length (it is even possible for them to have different lengths)</p><p>Every stripe can be cut into two or more parts. The cuttings are made perpendicularly to the side along which the length is measured. Thus the cuttings do not change the width of a stripe but each of the resulting pieces has a lesser length (the sum of which is equal to the length of the initial stripe)</p><p>After all the cuttings the blinds are constructed through consecutive joining of several parts, similar in length, along sides, along which length is measured. Also, apart from the resulting pieces an initial stripe can be used as a blind if it hasn't been cut. It is forbidden to construct blinds in any other way.</p><p>Thus, if the blinds consist of <span class=\"tex-span\"><i>k</i></span> pieces each <span class=\"tex-span\"><i>d</i></span> in length, then they are of form of a rectangle of <span class=\"tex-span\"><i>k</i> × <i>d</i></span> bourlemeters. </p><p>Your task is to find for what window possessing the largest possible area the blinds can be made from the given stripes if on technical grounds it is forbidden to use pieces shorter than <span class=\"tex-span\"><i>l</i></span> bourlemeter. The window is of form of a rectangle with side lengths as positive integers.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first output line contains two space-separated integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>l</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>l</i> ≤ 100</span>). They are the number of stripes in the warehouse and the minimal acceptable length of a blind stripe in bourlemeters. The second line contains space-separated <span class=\"tex-span\"><i>n</i></span> integers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span>. They are the lengths of initial stripes in bourlemeters (<span class=\"tex-span\">1 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the single number — the maximal area of the window in square bourlemeters that can be completely covered. If no window with a positive area that can be covered completely without breaking any of the given rules exist, then print the single number <span class=\"tex-span\">0</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4 2<br />1 2 3 4<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>8<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5 3<br />5 5 7 3 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>15<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 3<br />1 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0<br /></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>In the first sample test the required window is <span class=\"tex-span\">2 × 4</span> in size and the blinds for it consist of 4 parts, each 2 bourlemeters long. One of the parts is the initial stripe with the length of 2, the other one is a part of a cut stripe with the length of 3 and the two remaining stripes are parts of a stripe with the length of 4 cut in halves.</p></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='4596eee11d2885b90c6642adbe10a57e'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n </label>\r\n </div>\r\n <div style=\"padding: 0 1em 1em 1em;text-align:right;\">\r\n <input style=\"height:1.65em;padding:0 0.75em;\" type=\"submit\" value=\"Find\"/>\r\n </div>\r\n </form>\r\n </div>\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".handleBox\").autocomplete(\"/data/handles\", {\r\n delay: 200,\r\n width: 200,\r\n selectFirst: false,\r\n matchContains: true,\r\n minChars: 3\r\n });\r\n $(\".handleForm\").attr(\"autocomplete\", \"off\").submit(function () {\r\n var link = \"/profile/userHandle\".replace(\r\n \"userHandle\", $(this).find(\".handleBox\").val()\r\n );\r\n window.location = link;\r\n return false;\r\n });\r\n });\n </script>\n\r\n\r\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Recent actions\n <div class=\"top-links\">\n </div>\n </div>\n <div class=\"recent-actions\">\r\n <ul>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a href=\"/blog/entry/121171\">An Interesting Tree Problem</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/.Danet\" title=\"Expert .Danet\" class=\"rated-user user-blue\">.Danet</a> →\r\n <a href=\"/blog/entry/121172\">[TLE on pretest1]</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/sszcdjr\" title=\"Master sszcdjr\" class=\"rated-user user-orange\">sszcdjr</a> →\r\n <a href=\"/blog/entry/119859\">Codeforces Round 896 (Div. 1, Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" 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(Разбор задачи C)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/NALP\" title=\"Master NALP\" class=\"rated-user user-orange\">NALP</a>,\r\n <span class=\"format-humantime\" title=\"Oct/31/2010 19:40\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h1>Задача C. "Жалюзи"</h1>Нетрудно понять, что для некоторой фиксированной длины полос жалюзи <span class=\"tex-span\"><i>x</i></span>, максимальное количество полос, которые можно получить, равно: <br /><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/6408b359e53178405bfb4756205554134b7fb4bb.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><br /><br />тогда переберем это значение <span class=\"tex-span\"><i>x</i> ≥ <i>l</i></span>, и найдем максимум выражения <span class=\"tex-span\"><i>x</i>· <i>f</i>(<i>x</i>)</span>. 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Vasya the Architect"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Vasya the Architect</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Once Vasya played bricks. All the bricks in the set had regular cubical shape. Vasya vas a talented architect, however the tower he built kept falling apart.</p><p>Let us consider the building process. Vasya takes a brick and puts it on top of the already built tower so that the sides of the brick are parallel to the sides of the bricks he has already used. Let's introduce a Cartesian coordinate system on the horizontal plane, where Vasya puts the first brick. Then the projection of brick number <span class=\"tex-span\"><i>i</i></span> on the plane is a square with sides parallel to the axes of coordinates with opposite corners in points <span class=\"tex-span\">(<i>x</i><sub class=\"lower-index\"><i>i</i>, 1</sub>, <i>y</i><sub class=\"lower-index\"><i>i</i>, 1</sub>)</span> and <span class=\"tex-span\">(<i>x</i><sub class=\"lower-index\"><i>i</i>, 2</sub>, <i>y</i><sub class=\"lower-index\"><i>i</i>, 2</sub>)</span>. The bricks are cast from homogeneous plastic and the weight of a brick <span class=\"tex-span\"><i>a</i> × <i>a</i> × <i>a</i></span> is <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\">3</sup></span> grams.</p><p>It is guaranteed that Vasya puts any brick except the first one on the previous one, that is the area of intersection of the upper side of the previous brick and the lower side of the next brick is always positive.</p><p>We (Vasya included) live in a normal world where the laws of physical statics work. And that is why, perhaps, if we put yet another brick, the tower will collapse under its own weight. Vasya puts the cubes consecutively one on top of the other until at least one cube loses the balance and falls down. If it happens, Vasya gets upset and stops the construction. Print the number of bricks in the maximal stable tower, that is the maximal number <span class=\"tex-span\"><i>m</i></span> satisfying the condition that all the towers consisting of bricks 1, 2, ..., <span class=\"tex-span\"><i>k</i></span> for every integer <span class=\"tex-span\"><i>k</i></span> from 1 to <span class=\"tex-span\"><i>m</i></span> remain stable.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input file contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100</span>) which is the number of bricks. Each of the next <span class=\"tex-span\"><i>n</i></span> lines contains four numbers <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i>, 1</sub>, <i>y</i><sub class=\"lower-index\"><i>i</i>, 1</sub>, <i>x</i><sub class=\"lower-index\"><i>i</i>, 2</sub>, <i>y</i><sub class=\"lower-index\"><i>i</i>, 2</sub></span> (<span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i>, 1</sub> ≠ <i>x</i><sub class=\"lower-index\"><i>i</i>, 2</sub>, |<i>x</i><sub class=\"lower-index\"><i>i</i>, 1</sub> - <i>x</i><sub class=\"lower-index\"><i>i</i>, 2</sub>| = |<i>y</i><sub class=\"lower-index\"><i>i</i>, 1</sub> - <i>y</i><sub class=\"lower-index\"><i>i</i>, 2</sub>|</span>) which are the coordinates of the opposite angles of the base of the brick number <span class=\"tex-span\"><i>i</i></span>. The coordinates are integers and their absolute value does not exceed <span class=\"tex-span\">50</span>. </p><p>The cubes are given in the order Vasya puts them. It is guaranteed that the area of intersection of the upper side of the brick number <span class=\"tex-span\"><i>i</i> - 1</span> and the lower side of the brick number <span class=\"tex-span\"><i>i</i></span> is strictly strictly greater than zero for all <span class=\"tex-span\"><i>i</i> ≥ 2</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the number of bricks in the maximal stable tower.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/>0 0 3 3<br/>1 0 4 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/>0 0 3 3<br/>2 0 5 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>0 0 3 3<br/>1 0 4 3<br/>2 0 5 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"5e0ffabd8480fc8c9e0909b18bf0036c\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"fbd794f7652711d83dbb2390881fc29f4cda1cfe\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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Codeforces.setupTutorials(\"/data/problemTutorial\");\n });\n </script>\n\n<script type=\"text/javascript\">\n var _gaq = _gaq || [];\n _gaq.push(['_setAccount', 'UA-743380-5']);\n _gaq.push(['_trackPageview']);\n\n (function () {\n var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;\n ga.src = (document.location.protocol == 'https:' ? 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/38\">School Personal Contest #1 (Winter Computer School 2010/11) - Codeforces Beta Round 38 (ACM-ICPC Rules)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='5e0ffabd8480fc8c9e0909b18bf0036c'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/38/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1900\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='5e0ffabd8480fc8c9e0909b18bf0036c'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"193\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='5e0ffabd8480fc8c9e0909b18bf0036c'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"193\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/800\" title=\"School Individual Contest #1 (WCS 2010/11) - Codeforces Beta Round #38 (ACM-ICPC Rules)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"158:159\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/812\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"776\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/815\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"777\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/816\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\" target=\"_blank\">Tutorial #3 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"778\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/805\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\" target=\"_blank\">Tutorial #4 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"772\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/806\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\" target=\"_blank\">Tutorial #5 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"773\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/807\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\" target=\"_blank\">Tutorial #6 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"774\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/808\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи D)\" target=\"_blank\">Tutorial #7 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"775\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. 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Vasya the Architect</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Once Vasya played bricks. All the bricks in the set had regular cubical shape. Vasya vas a talented architect, however the tower he built kept falling apart.</p><p>Let us consider the building process. Vasya takes a brick and puts it on top of the already built tower so that the sides of the brick are parallel to the sides of the bricks he has already used. Let's introduce a Cartesian coordinate system on the horizontal plane, where Vasya puts the first brick. Then the projection of brick number <span class=\"tex-span\"><i>i</i></span> on the plane is a square with sides parallel to the axes of coordinates with opposite corners in points <span class=\"tex-span\">(<i>x</i><sub class=\"lower-index\"><i>i</i>, 1</sub>, <i>y</i><sub class=\"lower-index\"><i>i</i>, 1</sub>)</span> and <span class=\"tex-span\">(<i>x</i><sub class=\"lower-index\"><i>i</i>, 2</sub>, <i>y</i><sub class=\"lower-index\"><i>i</i>, 2</sub>)</span>. The bricks are cast from homogeneous plastic and the weight of a brick <span class=\"tex-span\"><i>a</i> × <i>a</i> × <i>a</i></span> is <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\">3</sup></span> grams.</p><p>It is guaranteed that Vasya puts any brick except the first one on the previous one, that is the area of intersection of the upper side of the previous brick and the lower side of the next brick is always positive.</p><p>We (Vasya included) live in a normal world where the laws of physical statics work. And that is why, perhaps, if we put yet another brick, the tower will collapse under its own weight. Vasya puts the cubes consecutively one on top of the other until at least one cube loses the balance and falls down. If it happens, Vasya gets upset and stops the construction. Print the number of bricks in the maximal stable tower, that is the maximal number <span class=\"tex-span\"><i>m</i></span> satisfying the condition that all the towers consisting of bricks 1, 2, ..., <span class=\"tex-span\"><i>k</i></span> for every integer <span class=\"tex-span\"><i>k</i></span> from 1 to <span class=\"tex-span\"><i>m</i></span> remain stable.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input file contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100</span>) which is the number of bricks. Each of the next <span class=\"tex-span\"><i>n</i></span> lines contains four numbers <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i>, 1</sub>, <i>y</i><sub class=\"lower-index\"><i>i</i>, 1</sub>, <i>x</i><sub class=\"lower-index\"><i>i</i>, 2</sub>, <i>y</i><sub class=\"lower-index\"><i>i</i>, 2</sub></span> (<span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i>, 1</sub> ≠ <i>x</i><sub class=\"lower-index\"><i>i</i>, 2</sub>, |<i>x</i><sub class=\"lower-index\"><i>i</i>, 1</sub> - <i>x</i><sub class=\"lower-index\"><i>i</i>, 2</sub>| = |<i>y</i><sub class=\"lower-index\"><i>i</i>, 1</sub> - <i>y</i><sub class=\"lower-index\"><i>i</i>, 2</sub>|</span>) which are the coordinates of the opposite angles of the base of the brick number <span class=\"tex-span\"><i>i</i></span>. The coordinates are integers and their absolute value does not exceed <span class=\"tex-span\">50</span>. </p><p>The cubes are given in the order Vasya puts them. It is guaranteed that the area of intersection of the upper side of the brick number <span class=\"tex-span\"><i>i</i> - 1</span> and the lower side of the brick number <span class=\"tex-span\"><i>i</i></span> is strictly strictly greater than zero for all <span class=\"tex-span\"><i>i</i> ≥ 2</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the number of bricks in the maximal stable tower.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br />0 0 3 3<br />1 0 4 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2<br />0 0 3 3<br />2 0 5 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />0 0 3 3<br />1 0 4 3<br />2 0 5 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='4596eee11d2885b90c6642adbe10a57e'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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(Разбор задачи C)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/NALP\" title=\"Master NALP\" class=\"rated-user user-orange\">NALP</a>,\r\n <span class=\"format-humantime\" title=\"Oct/31/2010 19:40\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h1>Задача C. "Жалюзи"</h1>Нетрудно понять, что для некоторой фиксированной длины полос жалюзи <span class=\"tex-span\"><i>x</i></span>, максимальное количество полос, которые можно получить, равно: <br /><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/6408b359e53178405bfb4756205554134b7fb4bb.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><br /><br />тогда переберем это значение <span class=\"tex-span\"><i>x</i> ≥ <i>l</i></span>, и найдем максимум выражения <span class=\"tex-span\"><i>x</i>· <i>f</i>(<i>x</i>)</span>. 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Let's Go Rolling!"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Let's Go Rolling!</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>On a number axis directed from the left rightwards, <span class=\"tex-span\"><i>n</i></span> marbles with coordinates <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\">1</sub>, <i>x</i><sub class=\"lower-index\">2</sub>, ..., <i>x</i><sub class=\"lower-index\"><i>n</i></sub></span> are situated. Let's assume that the sizes of the marbles are infinitely small, that is in this task each of them is assumed to be a material point. You can stick pins in some of them and the cost of sticking in the marble number <span class=\"tex-span\"><i>i</i></span> is equal to <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span>, number <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> may be negative. After you choose and stick the pins you need, the marbles will start to roll left according to the rule: if a marble has a pin stuck in it, then the marble doesn't move, otherwise the marble rolls all the way up to the next marble which has a pin stuck in it and stops moving there. If there is no pinned marble on the left to the given unpinned one, it is concluded that the marble rolls to the left to infinity and you will pay an infinitely large fine for it. If no marble rolled infinitely to the left, then the fine will consist of two summands: </p><ul> <li> the sum of the costs of stuck pins; </li><li> the sum of the lengths of the paths of each of the marbles, that is the sum of absolute values of differences between their initial and final positions. </li></ul><p>Your task is to choose and pin some marbles in the way that will make the fine for you to pay as little as possible.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 3000</span>) which is the number of marbles. The next <span class=\"tex-span\"><i>n</i></span> lines contain the descriptions of the marbles in pairs of integers <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\"> - 10<sup class=\"upper-index\">9</sup> ≤ <i>x</i><sub class=\"lower-index\"><i>i</i></sub>, <i>c</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>). The numbers are space-separated. Each description is given on a separate line. No two marbles have identical initial positions.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the single number — the least fine you will have to pay.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>2 3<br/>3 4<br/>1 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>1 7<br/>3 1<br/>5 10<br/>6 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>11<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"0bdd6d61415ede8169c4d31868ab7255\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"fbd794f7652711d83dbb2390881fc29f4cda1cfe\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/38\">School Personal Contest #1 (Winter Computer School 2010/11) - Codeforces Beta Round 38 (ACM-ICPC Rules)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='0bdd6d61415ede8169c4d31868ab7255'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/38/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Dynamic programming\">\r\n dp\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Sortings, orderings\">\r\n sortings\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1800\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='0bdd6d61415ede8169c4d31868ab7255'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"194\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='0bdd6d61415ede8169c4d31868ab7255'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"194\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/800\" title=\"School Individual Contest #1 (WCS 2010/11) - Codeforces Beta Round #38 (ACM-ICPC Rules)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"158:159\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/812\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"776\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/815\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"777\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/816\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\" target=\"_blank\">Tutorial #3 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"778\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/805\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\" target=\"_blank\">Tutorial #4 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"772\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/806\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\" target=\"_blank\">Tutorial #5 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"773\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/807\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\" target=\"_blank\">Tutorial #6 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"774\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/808\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи D)\" target=\"_blank\">Tutorial #7 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"775\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. 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Let's Go Rolling!</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>On a number axis directed from the left rightwards, <span class=\"tex-span\"><i>n</i></span> marbles with coordinates <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\">1</sub>, <i>x</i><sub class=\"lower-index\">2</sub>, ..., <i>x</i><sub class=\"lower-index\"><i>n</i></sub></span> are situated. Let's assume that the sizes of the marbles are infinitely small, that is in this task each of them is assumed to be a material point. You can stick pins in some of them and the cost of sticking in the marble number <span class=\"tex-span\"><i>i</i></span> is equal to <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span>, number <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> may be negative. After you choose and stick the pins you need, the marbles will start to roll left according to the rule: if a marble has a pin stuck in it, then the marble doesn't move, otherwise the marble rolls all the way up to the next marble which has a pin stuck in it and stops moving there. If there is no pinned marble on the left to the given unpinned one, it is concluded that the marble rolls to the left to infinity and you will pay an infinitely large fine for it. If no marble rolled infinitely to the left, then the fine will consist of two summands: </p><ul> <li> the sum of the costs of stuck pins; </li><li> the sum of the lengths of the paths of each of the marbles, that is the sum of absolute values of differences between their initial and final positions. </li></ul><p>Your task is to choose and pin some marbles in the way that will make the fine for you to pay as little as possible.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 3000</span>) which is the number of marbles. The next <span class=\"tex-span\"><i>n</i></span> lines contain the descriptions of the marbles in pairs of integers <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\"> - 10<sup class=\"upper-index\">9</sup> ≤ <i>x</i><sub class=\"lower-index\"><i>i</i></sub>, <i>c</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>). The numbers are space-separated. Each description is given on a separate line. No two marbles have identical initial positions.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the single number — the least fine you will have to pay.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />2 3<br />3 4<br />1 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />1 7<br />3 1<br />5 10<br />6 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>11<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=E]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='4596eee11d2885b90c6642adbe10a57e'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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(Разбор задачи C)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/NALP\" title=\"Master NALP\" class=\"rated-user user-orange\">NALP</a>,\r\n <span class=\"format-humantime\" title=\"Oct/31/2010 19:40\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h1>Задача C. "Жалюзи"</h1>Нетрудно понять, что для некоторой фиксированной длины полос жалюзи <span class=\"tex-span\"><i>x</i></span>, максимальное количество полос, которые можно получить, равно: <br /><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/6408b359e53178405bfb4756205554134b7fb4bb.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><br /><br />тогда переберем это значение <span class=\"tex-span\"><i>x</i> ≥ <i>l</i></span>, и найдем максимум выражения <span class=\"tex-span\"><i>x</i>· <i>f</i>(<i>x</i>)</span>. 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Smart Boy"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">F. Smart Boy</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>4 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Once Petya and Vasya invented a new game and called it \"Smart Boy\". They located a certain set of words — the dictionary — for the game. It is admissible for the dictionary to contain similar words. </p><p>The rules of the game are as follows: first the first player chooses any letter (a word as long as <span class=\"tex-span\">1</span>) from any word from the dictionary and writes it down on a piece of paper. The second player adds some other letter to this one's initial or final position, thus making a word as long as <span class=\"tex-span\">2</span>, then it's the first player's turn again, he adds a letter in the beginning or in the end thus making a word as long as <span class=\"tex-span\">3</span> and so on. But the player mustn't break one condition: the newly created word must be a substring of a word from a dictionary. The player who can't add a letter to the current word without breaking the condition loses.</p><p>Also if by the end of a turn a certain string <span class=\"tex-span\"><i>s</i></span> is written on paper, then the player, whose turn it just has been, gets a number of points according to the formula:</p><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/831de813618e0dc55fa0e07c8768f46b91d18927.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/></center><p>where </p><ul> <li> <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ba84be02bcc8a18469dd8faac3056b4c4eb0054f.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/> is a sequence number of symbol <span class=\"tex-span\"><i>c</i></span> in Latin alphabet, numbered starting from <span class=\"tex-span\">1</span>. For example, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/691184ea4a48c6be138dfe5989d6d0e5e3184a6b.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/>, and <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a92af08618cdbc859838ca588e67ffbee1b7683d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/>. </li><li> <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/52774077a8c15647cbf170fd26873d90f60c914a.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/> is the number of words from the dictionary where the line <span class=\"tex-span\"><i>s</i></span> occurs as a substring at least once. </li></ul><p>Your task is to learn who will win the game and what the final score will be. Every player plays optimally and most of all tries to win, then — to maximize the number of his points, then — to minimize the number of the points of the opponent.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>n</i></span> which is the number of words in the located dictionary <span class=\"tex-span\">(1 ≤ <i>n</i> ≤ 30)</span>. The <span class=\"tex-span\"><i>n</i></span> lines contain the words from the dictionary — one word is written on one line. Those lines are nonempty, consisting of Latin lower-case characters no longer than <span class=\"tex-span\">30</span> characters. Equal words can be in the list of words.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>On the first output line print a line \"First\" or \"Second\" which means who will win the game. On the second line output the number of points of the first player and the number of points of the second player after the game ends. Separate the numbers by a single space.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/>aba<br/>abac<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Second<br/>29 35<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>artem<br/>nik<br/>max<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>First<br/>2403 1882<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"6eca01d6b20ec3436e853cb8bcdaccfe\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - F - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"fbd794f7652711d83dbb2390881fc29f4cda1cfe\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - F - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/38\">School Personal Contest #1 (Winter Computer School 2010/11) - Codeforces Beta Round 38 (ACM-ICPC Rules)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='6eca01d6b20ec3436e853cb8bcdaccfe'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/38/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Dynamic programming\">\r\n dp\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Games, Sprague–Grundy theorem\">\r\n games\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Prefix- and Z-functions, suffix structures, Knuth–Morris–Pratt algorithm, etc\">\r\n strings\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2100\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='6eca01d6b20ec3436e853cb8bcdaccfe'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"195\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='6eca01d6b20ec3436e853cb8bcdaccfe'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"195\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/800\" title=\"School Individual Contest #1 (WCS 2010/11) - Codeforces Beta Round #38 (ACM-ICPC Rules)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"158:159\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/812\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"776\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/815\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"777\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/816\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\" target=\"_blank\">Tutorial #3 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"778\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/805\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\" target=\"_blank\">Tutorial #4 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"772\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/806\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\" target=\"_blank\">Tutorial #5 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"773\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/807\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\" target=\"_blank\">Tutorial #6 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"774\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/808\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи D)\" target=\"_blank\">Tutorial #7 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"775\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. 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Smart Boy</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>4 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Once Petya and Vasya invented a new game and called it "Smart Boy". They located a certain set of words — the dictionary — for the game. It is admissible for the dictionary to contain similar words. </p><p>The rules of the game are as follows: first the first player chooses any letter (a word as long as <span class=\"tex-span\">1</span>) from any word from the dictionary and writes it down on a piece of paper. The second player adds some other letter to this one's initial or final position, thus making a word as long as <span class=\"tex-span\">2</span>, then it's the first player's turn again, he adds a letter in the beginning or in the end thus making a word as long as <span class=\"tex-span\">3</span> and so on. But the player mustn't break one condition: the newly created word must be a substring of a word from a dictionary. The player who can't add a letter to the current word without breaking the condition loses.</p><p>Also if by the end of a turn a certain string <span class=\"tex-span\"><i>s</i></span> is written on paper, then the player, whose turn it just has been, gets a number of points according to the formula:</p><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/831de813618e0dc55fa0e07c8768f46b91d18927.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><p>where </p><ul> <li> <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ba84be02bcc8a18469dd8faac3056b4c4eb0054f.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> is a sequence number of symbol <span class=\"tex-span\"><i>c</i></span> in Latin alphabet, numbered starting from <span class=\"tex-span\">1</span>. For example, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/691184ea4a48c6be138dfe5989d6d0e5e3184a6b.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, and <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a92af08618cdbc859838ca588e67ffbee1b7683d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. </li><li> <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/52774077a8c15647cbf170fd26873d90f60c914a.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> is the number of words from the dictionary where the line <span class=\"tex-span\"><i>s</i></span> occurs as a substring at least once. </li></ul><p>Your task is to learn who will win the game and what the final score will be. Every player plays optimally and most of all tries to win, then — to maximize the number of his points, then — to minimize the number of the points of the opponent.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>n</i></span> which is the number of words in the located dictionary <span class=\"tex-span\">(1 ≤ <i>n</i> ≤ 30)</span>. The <span class=\"tex-span\"><i>n</i></span> lines contain the words from the dictionary — one word is written on one line. Those lines are nonempty, consisting of Latin lower-case characters no longer than <span class=\"tex-span\">30</span> characters. Equal words can be in the list of words.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>On the first output line print a line "First" or "Second" which means who will win the game. On the second line output the number of points of the first player and the number of points of the second player after the game ends. Separate the numbers by a single space.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br />aba<br />abac<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Second<br />29 35<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />artem<br />nik<br />max<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>First<br />2403 1882<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=F]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='4596eee11d2885b90c6642adbe10a57e'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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(Разбор задачи C)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/NALP\" title=\"Master NALP\" class=\"rated-user user-orange\">NALP</a>,\r\n <span class=\"format-humantime\" title=\"Oct/31/2010 19:40\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h1>Задача C. "Жалюзи"</h1>Нетрудно понять, что для некоторой фиксированной длины полос жалюзи <span class=\"tex-span\"><i>x</i></span>, максимальное количество полос, которые можно получить, равно: <br /><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/6408b359e53178405bfb4756205554134b7fb4bb.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><br /><br />тогда переберем это значение <span class=\"tex-span\"><i>x</i> ≥ <i>l</i></span>, и найдем максимум выражения <span class=\"tex-span\"><i>x</i>· <i>f</i>(<i>x</i>)</span>. 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Queue"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">G. Queue</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>On a cold winter evening our hero Vasya stood in a railway queue to buy a ticket for Codeforces championship final. As it usually happens, the cashier said he was going to be away for 5 minutes and left for an hour. Then Vasya, not to get bored, started to analyze such a mechanism as a queue. The findings astonished Vasya.</p><p>Every man is characterized by two numbers: <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span>, which is the importance of his current task (the greater the number is, the more important the task is) and number <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span>, which is a picture of his conscience. Numbers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> form the permutation of numbers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>.</p><p>Let the queue consist of <span class=\"tex-span\"><i>n</i> - 1</span> people at the moment. Let's look at the way the person who came number <span class=\"tex-span\"><i>n</i></span> behaves. First, he stands at the end of the queue and the does the following: if importance of the task <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> of the man in front of him is less than <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>n</i></sub></span>, they swap their places (it looks like this: the man number <span class=\"tex-span\"><i>n</i></span> asks the one before him: \"Erm... Excuse me please but it's very important for me... could you please let me move up the queue?\"), then he again poses the question to the man in front of him and so on. But in case when <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> is greater than <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>n</i></sub></span>, moving up the queue stops. However, the man number <span class=\"tex-span\"><i>n</i></span> can perform the operation no more than <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>n</i></sub></span> times.</p><p>In our task let us suppose that by the moment when the man number <span class=\"tex-span\"><i>n</i></span> joins the queue, the process of swaps between <span class=\"tex-span\"><i>n</i> - 1</span> will have stopped. If the swap is possible it necessarily takes place.</p><p>Your task is to help Vasya model the described process and find the order in which the people will stand in queue when all the swaps stops.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>n</i></span> which is the number of people who has joined the queue (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">5</sup></span>). In the next <span class=\"tex-span\"><i>n</i></span> lines descriptions of the people are given in order of their coming — space-separated integers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>n</i></span>, <span class=\"tex-span\">0 ≤ <i>c</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>n</i></span>). Every description is located on s single line. All the <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span>'s are different.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the permutation of numbers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>, which signifies the queue formed according to the above described rules, starting from the beginning to the end. In this succession the <span class=\"tex-span\"><i>i</i></span>-th number stands for the number of a person who will stand in line on the place number <span class=\"tex-span\"><i>i</i></span> after the swaps ends. People are numbered starting with <span class=\"tex-span\">1</span> in the order in which they were given in the input. Separate numbers by a space.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/>1 0<br/>2 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 1 </pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>1 3<br/>2 3<br/>3 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3 2 1 </pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5<br/>2 3<br/>1 4<br/>4 3<br/>3 1<br/>5 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3 1 5 4 2 </pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"7ea2d33abfeeaa97006f4cba96edb642\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - G - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"fbd794f7652711d83dbb2390881fc29f4cda1cfe\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - G - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='7ea2d33abfeeaa97006f4cba96edb642'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/38/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Heaps, binary search trees, segment trees, hash tables, etc\">\r\n data structures\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2300\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='7ea2d33abfeeaa97006f4cba96edb642'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"196\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='7ea2d33abfeeaa97006f4cba96edb642'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"196\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/800\" title=\"School Individual Contest #1 (WCS 2010/11) - Codeforces Beta Round #38 (ACM-ICPC Rules)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"158:159\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/812\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"776\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/815\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"777\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/816\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\" target=\"_blank\">Tutorial #3 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"778\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/805\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\" target=\"_blank\">Tutorial #4 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"772\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/806\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\" target=\"_blank\">Tutorial #5 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"773\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/807\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\" target=\"_blank\">Tutorial #6 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"774\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/808\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи D)\" target=\"_blank\">Tutorial #7 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"775\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. 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Queue</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>On a cold winter evening our hero Vasya stood in a railway queue to buy a ticket for Codeforces championship final. As it usually happens, the cashier said he was going to be away for 5 minutes and left for an hour. Then Vasya, not to get bored, started to analyze such a mechanism as a queue. The findings astonished Vasya.</p><p>Every man is characterized by two numbers: <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span>, which is the importance of his current task (the greater the number is, the more important the task is) and number <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span>, which is a picture of his conscience. Numbers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> form the permutation of numbers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>.</p><p>Let the queue consist of <span class=\"tex-span\"><i>n</i> - 1</span> people at the moment. Let's look at the way the person who came number <span class=\"tex-span\"><i>n</i></span> behaves. First, he stands at the end of the queue and the does the following: if importance of the task <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> of the man in front of him is less than <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>n</i></sub></span>, they swap their places (it looks like this: the man number <span class=\"tex-span\"><i>n</i></span> asks the one before him: "Erm... Excuse me please but it's very important for me... could you please let me move up the queue?"), then he again poses the question to the man in front of him and so on. But in case when <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> is greater than <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>n</i></sub></span>, moving up the queue stops. However, the man number <span class=\"tex-span\"><i>n</i></span> can perform the operation no more than <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>n</i></sub></span> times.</p><p>In our task let us suppose that by the moment when the man number <span class=\"tex-span\"><i>n</i></span> joins the queue, the process of swaps between <span class=\"tex-span\"><i>n</i> - 1</span> will have stopped. If the swap is possible it necessarily takes place.</p><p>Your task is to help Vasya model the described process and find the order in which the people will stand in queue when all the swaps stops.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>n</i></span> which is the number of people who has joined the queue (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">5</sup></span>). In the next <span class=\"tex-span\"><i>n</i></span> lines descriptions of the people are given in order of their coming — space-separated integers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>n</i></span>, <span class=\"tex-span\">0 ≤ <i>c</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>n</i></span>). Every description is located on s single line. All the <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span>'s are different.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the permutation of numbers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>, which signifies the queue formed according to the above described rules, starting from the beginning to the end. In this succession the <span class=\"tex-span\"><i>i</i></span>-th number stands for the number of a person who will stand in line on the place number <span class=\"tex-span\"><i>i</i></span> after the swaps ends. People are numbered starting with <span class=\"tex-span\">1</span> in the order in which they were given in the input. Separate numbers by a space.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br />1 0<br />2 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 1 </pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />1 3<br />2 3<br />3 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3 2 1 </pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5<br />2 3<br />1 4<br />4 3<br />3 1<br />5 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3 1 5 4 2 </pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=G]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='4596eee11d2885b90c6642adbe10a57e'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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(Разбор задачи C)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/NALP\" title=\"Master NALP\" class=\"rated-user user-orange\">NALP</a>,\r\n <span class=\"format-humantime\" title=\"Oct/31/2010 19:40\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h1>Задача C. "Жалюзи"</h1>Нетрудно понять, что для некоторой фиксированной длины полос жалюзи <span class=\"tex-span\"><i>x</i></span>, максимальное количество полос, которые можно получить, равно: <br /><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/6408b359e53178405bfb4756205554134b7fb4bb.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><br /><br />тогда переберем это значение <span class=\"tex-span\"><i>x</i> ≥ <i>l</i></span>, и найдем максимум выражения <span class=\"tex-span\"><i>x</i>· <i>f</i>(<i>x</i>)</span>. 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The Great Marathon"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">H. The Great Marathon</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>4 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>On the Berland Dependence Day it was decided to organize a great marathon. Berland consists of <span class=\"tex-span\"><i>n</i></span> cities, some of which are linked by two-way roads. Each road has a certain length. The cities are numbered from 1 to <span class=\"tex-span\"><i>n</i></span>. It is known that one can get from any city to any other one by the roads.</p><p><span class=\"tex-span\"><i>n</i></span> runners take part in the competition, one from each city. But Berland runners are talkative by nature and that's why the juries took measures to avoid large crowds of marathon participants. The jury decided that every runner should start the marathon from their hometown. Before the start every sportsman will get a piece of paper containing the name of the city where the sportsman's finishing line is. The finish is chosen randomly for every sportsman but it can't coincide with the sportsman's starting point. Several sportsmen are allowed to finish in one and the same city. All the sportsmen start simultaneously and everyone runs the shortest route from the starting point to the finishing one. All the sportsmen run at one speed which equals to <span class=\"tex-span\">1</span>.</p><p>After the competition a follow-up table of the results will be composed where the sportsmen will be sorted according to the nondecrease of time they spent to cover the distance. The first <span class=\"tex-span\"><i>g</i></span> sportsmen in the table will get golden medals, the next <span class=\"tex-span\"><i>s</i></span> sportsmen will get silver medals and the rest will get bronze medals. Besides, if two or more sportsmen spend the same amount of time to cover the distance, they are sorted according to the number of the city where a sportsman started to run in the ascending order. That means no two sportsmen share one and the same place.</p><p>According to the rules of the competition the number of gold medals <span class=\"tex-span\"><i>g</i></span> must satisfy the inequation <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">1</sub> ≤ <i>g</i> ≤ <i>g</i><sub class=\"lower-index\">2</sub></span>, where <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">2</sub></span> are values formed historically. In a similar way, the number of silver medals <span class=\"tex-span\"><i>s</i></span> must satisfy the inequation <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">1</sub> ≤ <i>s</i> ≤ <i>s</i><sub class=\"lower-index\">2</sub></span>, where <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">2</sub></span> are also values formed historically.</p><p>At present, before the start of the competition, the destination points of every sportsman are unknown. However, the press demands details and that's why you are given the task of counting the number of the ways to distribute the medals. Two ways to distribute the medals are considered different if at least one sportsman could have received during those distributions different kinds of medals.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains given integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">3 ≤ <i>n</i> ≤ 50</span>, <span class=\"tex-span\"><i>n</i> - 1 ≤ <i>m</i> ≤ 1000</span>), where <span class=\"tex-span\"><i>n</i></span> is the number of Berland towns and <span class=\"tex-span\"><i>m</i></span> is the number of roads.</p><p>Next in <span class=\"tex-span\"><i>m</i></span> lines road descriptions are given as groups of three integers <span class=\"tex-span\"><i>v</i></span>, <span class=\"tex-span\"><i>u</i></span>, <span class=\"tex-span\"><i>c</i></span>, which are the numbers of linked towns and its length (<span class=\"tex-span\">1 ≤ <i>v</i>, <i>u</i> ≤ <i>n</i></span>, <span class=\"tex-span\"><i>v</i> ≠ <i>u</i></span>, <span class=\"tex-span\">1 ≤ <i>c</i> ≤ 1000</span>). Every pair of cities have no more than one road between them.</p><p>The last line contains integers <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">2</sub></span>, <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">2</sub></span> (<span class=\"tex-span\">1 ≤ <i>g</i><sub class=\"lower-index\">1</sub> ≤ <i>g</i><sub class=\"lower-index\">2</sub></span>, <span class=\"tex-span\">1 ≤ <i>s</i><sub class=\"lower-index\">1</sub> ≤ <i>s</i><sub class=\"lower-index\">2</sub></span>, <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">2</sub> + <i>s</i><sub class=\"lower-index\">2</sub> < <i>n</i></span>). The input data numbers, located on one line, are space-separated.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the single number — the number of ways to distribute the medals. It is guaranteed that the number fits in the standard 64-bit signed data type.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 2<br/>1 2 1<br/>2 3 1<br/>1 1 1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 5<br/>1 2 2<br/>2 3 1<br/>3 4 2<br/>4 1 2<br/>1 3 3<br/>1 2 1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>19<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br/>1 2 2<br/>2 3 1<br/>3 1 2<br/>1 1 1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"abf9c7f40b2d0c250af52a17ed82edce\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - H - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"fbd794f7652711d83dbb2390881fc29f4cda1cfe\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - H - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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Codeforces.setupTutorials(\"/data/problemTutorial\");\n });\n </script>\n\n<script type=\"text/javascript\">\n var _gaq = _gaq || [];\n _gaq.push(['_setAccount', 'UA-743380-5']);\n _gaq.push(['_trackPageview']);\n\n (function () {\n var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;\n ga.src = (document.location.protocol == 'https:' ? 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/38\">School Personal Contest #1 (Winter Computer School 2010/11) - Codeforces Beta Round 38 (ACM-ICPC Rules)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='abf9c7f40b2d0c250af52a17ed82edce'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/38/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Dynamic programming\">\r\n dp\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2400\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='abf9c7f40b2d0c250af52a17ed82edce'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"197\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='abf9c7f40b2d0c250af52a17ed82edce'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"197\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/800\" title=\"School Individual Contest #1 (WCS 2010/11) - Codeforces Beta Round #38 (ACM-ICPC Rules)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"158:159\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/812\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"776\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи C)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/815\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"777\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи E)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/816\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\" target=\"_blank\">Tutorial #3 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"778\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи F)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/805\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\" target=\"_blank\">Tutorial #4 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"772\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи A)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/806\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\" target=\"_blank\">Tutorial #5 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"773\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи B)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/807\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\" target=\"_blank\">Tutorial #6 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"774\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи G)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/808\" title=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. (Разбор задачи D)\" target=\"_blank\">Tutorial #7 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"775\" resourceName=\"Школьная индивидуальная олимпиада #1 - Codeforces Beta Round #38. 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The Great Marathon</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>4 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>On the Berland Dependence Day it was decided to organize a great marathon. Berland consists of <span class=\"tex-span\"><i>n</i></span> cities, some of which are linked by two-way roads. Each road has a certain length. The cities are numbered from 1 to <span class=\"tex-span\"><i>n</i></span>. It is known that one can get from any city to any other one by the roads.</p><p><span class=\"tex-span\"><i>n</i></span> runners take part in the competition, one from each city. But Berland runners are talkative by nature and that's why the juries took measures to avoid large crowds of marathon participants. The jury decided that every runner should start the marathon from their hometown. Before the start every sportsman will get a piece of paper containing the name of the city where the sportsman's finishing line is. The finish is chosen randomly for every sportsman but it can't coincide with the sportsman's starting point. Several sportsmen are allowed to finish in one and the same city. All the sportsmen start simultaneously and everyone runs the shortest route from the starting point to the finishing one. All the sportsmen run at one speed which equals to <span class=\"tex-span\">1</span>.</p><p>After the competition a follow-up table of the results will be composed where the sportsmen will be sorted according to the nondecrease of time they spent to cover the distance. The first <span class=\"tex-span\"><i>g</i></span> sportsmen in the table will get golden medals, the next <span class=\"tex-span\"><i>s</i></span> sportsmen will get silver medals and the rest will get bronze medals. Besides, if two or more sportsmen spend the same amount of time to cover the distance, they are sorted according to the number of the city where a sportsman started to run in the ascending order. That means no two sportsmen share one and the same place.</p><p>According to the rules of the competition the number of gold medals <span class=\"tex-span\"><i>g</i></span> must satisfy the inequation <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">1</sub> ≤ <i>g</i> ≤ <i>g</i><sub class=\"lower-index\">2</sub></span>, where <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">2</sub></span> are values formed historically. In a similar way, the number of silver medals <span class=\"tex-span\"><i>s</i></span> must satisfy the inequation <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">1</sub> ≤ <i>s</i> ≤ <i>s</i><sub class=\"lower-index\">2</sub></span>, where <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">2</sub></span> are also values formed historically.</p><p>At present, before the start of the competition, the destination points of every sportsman are unknown. However, the press demands details and that's why you are given the task of counting the number of the ways to distribute the medals. Two ways to distribute the medals are considered different if at least one sportsman could have received during those distributions different kinds of medals.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains given integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">3 ≤ <i>n</i> ≤ 50</span>, <span class=\"tex-span\"><i>n</i> - 1 ≤ <i>m</i> ≤ 1000</span>), where <span class=\"tex-span\"><i>n</i></span> is the number of Berland towns and <span class=\"tex-span\"><i>m</i></span> is the number of roads.</p><p>Next in <span class=\"tex-span\"><i>m</i></span> lines road descriptions are given as groups of three integers <span class=\"tex-span\"><i>v</i></span>, <span class=\"tex-span\"><i>u</i></span>, <span class=\"tex-span\"><i>c</i></span>, which are the numbers of linked towns and its length (<span class=\"tex-span\">1 ≤ <i>v</i>, <i>u</i> ≤ <i>n</i></span>, <span class=\"tex-span\"><i>v</i> ≠ <i>u</i></span>, <span class=\"tex-span\">1 ≤ <i>c</i> ≤ 1000</span>). Every pair of cities have no more than one road between them.</p><p>The last line contains integers <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">2</sub></span>, <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>s</i><sub class=\"lower-index\">2</sub></span> (<span class=\"tex-span\">1 ≤ <i>g</i><sub class=\"lower-index\">1</sub> ≤ <i>g</i><sub class=\"lower-index\">2</sub></span>, <span class=\"tex-span\">1 ≤ <i>s</i><sub class=\"lower-index\">1</sub> ≤ <i>s</i><sub class=\"lower-index\">2</sub></span>, <span class=\"tex-span\"><i>g</i><sub class=\"lower-index\">2</sub> + <i>s</i><sub class=\"lower-index\">2</sub> < <i>n</i></span>). The input data numbers, located on one line, are space-separated.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the single number — the number of ways to distribute the medals. It is guaranteed that the number fits in the standard 64-bit signed data type.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 2<br />1 2 1<br />2 3 1<br />1 1 1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 5<br />1 2 2<br />2 3 1<br />3 4 2<br />4 1 2<br />1 3 3<br />1 2 1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>19<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br />1 2 2<br />2 3 1<br />3 1 2<br />1 1 1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=H]\");\r\n let uuid = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='4596eee11d2885b90c6642adbe10a57e'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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(Разбор задачи C)\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/NALP\" title=\"Master NALP\" class=\"rated-user user-orange\">NALP</a>,\r\n <span class=\"format-humantime\" title=\"Oct/31/2010 19:40\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h1>Задача C. "Жалюзи"</h1>Нетрудно понять, что для некоторой фиксированной длины полос жалюзи <span class=\"tex-span\"><i>x</i></span>, максимальное количество полос, которые можно получить, равно: <br /><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/6408b359e53178405bfb4756205554134b7fb4bb.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><br /><br />тогда переберем это значение <span class=\"tex-span\"><i>x</i> ≥ <i>l</i></span>, и найдем максимум выражения <span class=\"tex-span\"><i>x</i>· <i>f</i>(<i>x</i>)</span>. 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C*++ Calculations"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. C*++ Calculations</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>C*++ language is quite similar to C++. The similarity manifests itself in the fact that the programs written in C*++ sometimes behave unpredictably and lead to absolutely unexpected effects. For example, let's imagine an arithmetic expression in C*++ that looks like this (<span class=\"tex-span\"><i>expression</i></span> is the main term):</p><ul> <li> <span class=\"tex-span\"><i>expression</i></span> ::= <span class=\"tex-span\"><i>summand</i></span> | <span class=\"tex-span\"><i>expression</i> + <i>summand</i></span> | <span class=\"tex-span\"><i>expression</i> - <i>summand</i></span> </li><li> <span class=\"tex-span\"><i>summand</i></span> ::= <span class=\"tex-span\"><i>increment</i></span> | <span class=\"tex-span\"><i>coefficient</i></span>*<span class=\"tex-span\"><i>increment</i></span> </li><li> <span class=\"tex-span\"><i>increment</i></span> ::= a++ | ++a </li><li> <span class=\"tex-span\"><i>coefficient</i></span> ::= 0|1|2|...|1000 </li></ul><p>For example, \"<span class=\"tex-font-style-tt\">5*a++-3*++a+a++</span>\" is a valid expression in C*++.</p><p>Thus, we have a sum consisting of several summands divided by signs \"<span class=\"tex-font-style-tt\">+</span>\" or \"<span class=\"tex-font-style-tt\">-</span>\". Every summand is an expression \"<span class=\"tex-font-style-tt\">a++</span>\" or \"<span class=\"tex-font-style-tt\">++a</span>\" multiplied by some integer coefficient. If the coefficient is omitted, it is suggested being equal to <span class=\"tex-span\">1</span>.</p><p>The calculation of such sum in C*++ goes the following way. First all the summands are calculated one after another, then they are summed by the usual arithmetic rules. If the summand contains \"<span class=\"tex-font-style-tt\">a++</span>\", then during the calculation first the value of the \"<span class=\"tex-font-style-tt\">a</span>\" variable is multiplied by the coefficient, then value of \"<span class=\"tex-font-style-tt\">a</span>\" is increased by <span class=\"tex-span\">1</span>. If the summand contains \"<span class=\"tex-font-style-tt\">++a</span>\", then the actions on it are performed in the reverse order: first \"<span class=\"tex-font-style-tt\">a</span>\" is increased by <span class=\"tex-span\">1</span>, then — multiplied by the coefficient.</p><p>The summands may be calculated in any order, that's why sometimes the result of the calculation is completely unpredictable! Your task is to find its largest possible value.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>a</i></span> (<span class=\"tex-span\"> - 1000 ≤ <i>a</i> ≤ 1000</span>) — the initial value of the variable \"<span class=\"tex-font-style-tt\">a</span>\". The next line contains an expression in C*++ language of the described type. The number of the summands in the expression does not exceed <span class=\"tex-span\">1000</span>. It is guaranteed that the line describing the expression contains no spaces and tabulation. </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a single number — the maximal possible value of the expression.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br/>5*a++-3*++a+a++<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>11<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>a+++++a<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>8<br/></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>Consider the second example. Initially <span class=\"tex-span\"><i>a</i> = 3</span>. Suppose that at first the first summand is calculated, and then the second one is. The first summand gets equal to <span class=\"tex-span\">3</span>, and the value of <span class=\"tex-span\"><i>a</i></span> is increased by <span class=\"tex-span\">1</span>. At the calculation of the second summand <span class=\"tex-span\"><i>a</i></span> is increased once more (gets equal to <span class=\"tex-span\">5</span>). The value of the second summand is <span class=\"tex-span\">5</span>, and together they give <span class=\"tex-span\">8</span>. If we calculate the second summand first and the first summand later, then the both summands equals to <span class=\"tex-span\">4</span>, and the result is <span class=\"tex-span\">8</span>, too.</p></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"2e7dab45407625c71e4f2a5123441d35\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='2e7dab45407625c71e4f2a5123441d35'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Parsing expression grammar\">\r\n expression parsing\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Greedy algorithms\">\r\n greedy\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2000\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='2e7dab45407625c71e4f2a5123441d35'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"174\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='2e7dab45407625c71e4f2a5123441d35'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"174\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/39\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/39/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/39/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/39/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/39/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/39/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n 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(!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_ec35e55f4d9cf88b3da69a37cf4a57cfaaaec9ca\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. C*++ Calculations</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>C*++ language is quite similar to C++. The similarity manifests itself in the fact that the programs written in C*++ sometimes behave unpredictably and lead to absolutely unexpected effects. For example, let's imagine an arithmetic expression in C*++ that looks like this (<span class=\"tex-span\"><i>expression</i></span> is the main term):</p><ul> <li> <span class=\"tex-span\"><i>expression</i></span> ::= <span class=\"tex-span\"><i>summand</i></span> | <span class=\"tex-span\"><i>expression</i> + <i>summand</i></span> | <span class=\"tex-span\"><i>expression</i> - <i>summand</i></span> </li><li> <span class=\"tex-span\"><i>summand</i></span> ::= <span class=\"tex-span\"><i>increment</i></span> | <span class=\"tex-span\"><i>coefficient</i></span>*<span class=\"tex-span\"><i>increment</i></span> </li><li> <span class=\"tex-span\"><i>increment</i></span> ::= a++ | ++a </li><li> <span class=\"tex-span\"><i>coefficient</i></span> ::= 0|1|2|...|1000 </li></ul><p>For example, "<span class=\"tex-font-style-tt\">5*a++-3*++a+a++</span>" is a valid expression in C*++.</p><p>Thus, we have a sum consisting of several summands divided by signs "<span class=\"tex-font-style-tt\">+</span>" or "<span class=\"tex-font-style-tt\">-</span>". Every summand is an expression "<span class=\"tex-font-style-tt\">a++</span>" or "<span class=\"tex-font-style-tt\">++a</span>" multiplied by some integer coefficient. If the coefficient is omitted, it is suggested being equal to <span class=\"tex-span\">1</span>.</p><p>The calculation of such sum in C*++ goes the following way. First all the summands are calculated one after another, then they are summed by the usual arithmetic rules. If the summand contains "<span class=\"tex-font-style-tt\">a++</span>", then during the calculation first the value of the "<span class=\"tex-font-style-tt\">a</span>" variable is multiplied by the coefficient, then value of "<span class=\"tex-font-style-tt\">a</span>" is increased by <span class=\"tex-span\">1</span>. If the summand contains "<span class=\"tex-font-style-tt\">++a</span>", then the actions on it are performed in the reverse order: first "<span class=\"tex-font-style-tt\">a</span>" is increased by <span class=\"tex-span\">1</span>, then — multiplied by the coefficient.</p><p>The summands may be calculated in any order, that's why sometimes the result of the calculation is completely unpredictable! Your task is to find its largest possible value.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first input line contains an integer <span class=\"tex-span\"><i>a</i></span> (<span class=\"tex-span\"> - 1000 ≤ <i>a</i> ≤ 1000</span>) — the initial value of the variable "<span class=\"tex-font-style-tt\">a</span>". The next line contains an expression in C*++ language of the described type. The number of the summands in the expression does not exceed <span class=\"tex-span\">1000</span>. It is guaranteed that the line describing the expression contains no spaces and tabulation. </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a single number — the maximal possible value of the expression.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br />5*a++-3*++a+a++<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>11<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />a+++++a<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>8<br /></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>Consider the second example. Initially <span class=\"tex-span\"><i>a</i> = 3</span>. Suppose that at first the first summand is calculated, and then the second one is. The first summand gets equal to <span class=\"tex-span\">3</span>, and the value of <span class=\"tex-span\"><i>a</i></span> is increased by <span class=\"tex-span\">1</span>. At the calculation of the second summand <span class=\"tex-span\"><i>a</i></span> is increased once more (gets equal to <span class=\"tex-span\">5</span>). The value of the second summand is <span class=\"tex-span\">5</span>, and together they give <span class=\"tex-span\">8</span>. 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=school\" class=\"tag notice\" style=\"text-decoration: none;\">school</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=team\" class=\"tag notice\" style=\"text-decoration: none;\">team</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+9</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/786#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/786#comments\">\n 5\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div 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Company Income Growth"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Company Income Growth</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Petya works as a PR manager for a successful Berland company BerSoft. He needs to prepare a presentation on the company income growth since <span class=\"tex-span\">2001</span> (the year of its founding) till now. Petya knows that in <span class=\"tex-span\">2001</span> the company income amounted to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub></span> billion bourles, in <span class=\"tex-span\">2002</span> — to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">2</sub></span> billion, ..., and in the current <span class=\"tex-span\">(2000 + <i>n</i>)</span>-th year — <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>n</i></sub></span> billion bourles. On the base of the information Petya decided to show in his presentation the linear progress history which is in his opinion perfect. According to a graph Petya has already made, in the first year BerSoft company income must amount to <span class=\"tex-span\">1</span> billion bourles, in the second year — <span class=\"tex-span\">2</span> billion bourles etc., each following year the income increases by <span class=\"tex-span\">1</span> billion bourles. Unfortunately, the real numbers are different from the perfect ones. Among the numbers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> can even occur negative ones that are a sign of the company’s losses in some years. That is why Petya wants to ignore some data, in other words, cross some numbers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> from the sequence and leave only some subsequence that has perfect growth.</p><p>Thus Petya has to choose a sequence of years <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\"><i>k</i></sub></span>,so that in the year <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">1</sub></span> the company income amounted to <span class=\"tex-span\">1</span> billion bourles, in the year <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">2</sub></span> — <span class=\"tex-span\">2</span> billion bourles etc., in accordance with the perfect growth dynamics. Help him to choose the longest such sequence.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100</span>). The next line contains <span class=\"tex-span\"><i>n</i></span> integers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\"> - 100 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>). The number <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> determines the income of BerSoft company in the <span class=\"tex-span\">(2000 + <i>i</i>)</span>-th year. The numbers in the line are separated by spaces.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output <span class=\"tex-span\"><i>k</i></span> — the maximum possible length of a perfect sequence. In the next line output the sequence of years <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\"><i>k</i></sub></span>. Separate the numbers by spaces. If the answer is not unique, output any. If no solution exist, output one number <span class=\"tex-span\">0</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>10<br/>-2 1 1 3 2 3 4 -10 -2 5<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br/>2002 2005 2006 2007 2010<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>-1 -2 -3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"81fdfed4543ed4e2267bf406f41b0f76\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='81fdfed4543ed4e2267bf406f41b0f76'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Greedy algorithms\">\r\n greedy\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1300\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='81fdfed4543ed4e2267bf406f41b0f76'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"175\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='81fdfed4543ed4e2267bf406f41b0f76'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"175\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/39\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/39/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/39/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/39/status\">Status</a></li>\r\n <li><a\r\n 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class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"B\" data-uuid=\"ps_c32b6f539a959af513767b30b9822cbd454f7aa6\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Company Income Growth</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Petya works as a PR manager for a successful Berland company BerSoft. He needs to prepare a presentation on the company income growth since <span class=\"tex-span\">2001</span> (the year of its founding) till now. Petya knows that in <span class=\"tex-span\">2001</span> the company income amounted to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub></span> billion bourles, in <span class=\"tex-span\">2002</span> — to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">2</sub></span> billion, ..., and in the current <span class=\"tex-span\">(2000 + <i>n</i>)</span>-th year — <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>n</i></sub></span> billion bourles. On the base of the information Petya decided to show in his presentation the linear progress history which is in his opinion perfect. According to a graph Petya has already made, in the first year BerSoft company income must amount to <span class=\"tex-span\">1</span> billion bourles, in the second year — <span class=\"tex-span\">2</span> billion bourles etc., each following year the income increases by <span class=\"tex-span\">1</span> billion bourles. Unfortunately, the real numbers are different from the perfect ones. Among the numbers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> can even occur negative ones that are a sign of the company’s losses in some years. That is why Petya wants to ignore some data, in other words, cross some numbers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> from the sequence and leave only some subsequence that has perfect growth.</p><p>Thus Petya has to choose a sequence of years <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\"><i>k</i></sub></span>,so that in the year <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">1</sub></span> the company income amounted to <span class=\"tex-span\">1</span> billion bourles, in the year <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">2</sub></span> — <span class=\"tex-span\">2</span> billion bourles etc., in accordance with the perfect growth dynamics. Help him to choose the longest such sequence.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100</span>). The next line contains <span class=\"tex-span\"><i>n</i></span> integers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\"> - 100 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 100</span>). The number <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> determines the income of BerSoft company in the <span class=\"tex-span\">(2000 + <i>i</i>)</span>-th year. The numbers in the line are separated by spaces.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output <span class=\"tex-span\"><i>k</i></span> — the maximum possible length of a perfect sequence. In the next line output the sequence of years <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>y</i><sub class=\"lower-index\"><i>k</i></sub></span>. Separate the numbers by spaces. If the answer is not unique, output any. If no solution exist, output one number <span class=\"tex-span\">0</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>10<br />-2 1 1 3 2 3 4 -10 -2 5<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br />2002 2005 2006 2007 2010<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />-1 -2 -3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=B]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, 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href=\"#\" class=\"topic-vote-up-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+9</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/786#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/786#comments\">\n 5\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div 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Moon Craters"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Moon Craters</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>There are lots of theories concerning the origin of moon craters. Most scientists stick to the meteorite theory, which says that the craters were formed as a result of celestial bodies colliding with the Moon. The other version is that the craters were parts of volcanoes.</p><p>An extraterrestrial intelligence research specialist professor Okulov (the namesake of the Okulov, the author of famous textbooks on programming) put forward an alternate hypothesis. Guess what kind of a hypothesis it was –– sure, the one including extraterrestrial mind involvement. Now the professor is looking for proofs of his hypothesis.</p><p>Professor has data from the moon robot that moves linearly in one direction along the Moon surface. The moon craters are circular in form with integer-valued radii. The moon robot records only the craters whose centers lay on his path and sends to the Earth the information on the distance from the centers of the craters to the initial point of its path and on the radii of the craters.</p><p>According to the theory of professor Okulov two craters made by an extraterrestrial intelligence for the aims yet unknown either are fully enclosed one in the other or do not intersect at all. Internal or external tangency is acceptable. However the experimental data from the moon robot do not confirm this theory! Nevertheless, professor Okulov is hopeful. He perfectly understands that to create any logical theory one has to ignore some data that are wrong due to faulty measuring (or skillful disguise by the extraterrestrial intelligence that will be sooner or later found by professor Okulov!) That’s why Okulov wants to choose among the available crater descriptions the largest set that would satisfy his theory.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line has an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 2000</span>) — the number of discovered craters. The next <span class=\"tex-span\"><i>n</i></span> lines contain crater descriptions in the \"<span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>\" format, where <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> is the coordinate of the center of the crater on the moon robot’s path, <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span> is the radius of the crater. All the numbers <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span> are positive integers not exceeding <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. No two craters coincide.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the number of craters in the required largest set. In the next line output space-separated numbers of craters that this set consists of. The craters are numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span> in the order in which they were given in the input data. The numbers may be output in any order. If the result is not unique, output any.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>1 1<br/>2 2<br/>4 1<br/>5 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br/>1 2 4<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"05b458296bc5e83140a221cac3a89d69\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='05b458296bc5e83140a221cac3a89d69'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Dynamic programming\">\r\n dp\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Sortings, orderings\">\r\n sortings\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2100\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='05b458296bc5e83140a221cac3a89d69'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"176\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='05b458296bc5e83140a221cac3a89d69'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"176\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current 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(!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"C\" data-uuid=\"ps_2f9842f11a8cd66d2c252cbcb8202c02aebd503f\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Moon Craters</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>There are lots of theories concerning the origin of moon craters. Most scientists stick to the meteorite theory, which says that the craters were formed as a result of celestial bodies colliding with the Moon. The other version is that the craters were parts of volcanoes.</p><p>An extraterrestrial intelligence research specialist professor Okulov (the namesake of the Okulov, the author of famous textbooks on programming) put forward an alternate hypothesis. Guess what kind of a hypothesis it was –– sure, the one including extraterrestrial mind involvement. Now the professor is looking for proofs of his hypothesis.</p><p>Professor has data from the moon robot that moves linearly in one direction along the Moon surface. The moon craters are circular in form with integer-valued radii. The moon robot records only the craters whose centers lay on his path and sends to the Earth the information on the distance from the centers of the craters to the initial point of its path and on the radii of the craters.</p><p>According to the theory of professor Okulov two craters made by an extraterrestrial intelligence for the aims yet unknown either are fully enclosed one in the other or do not intersect at all. Internal or external tangency is acceptable. However the experimental data from the moon robot do not confirm this theory! Nevertheless, professor Okulov is hopeful. He perfectly understands that to create any logical theory one has to ignore some data that are wrong due to faulty measuring (or skillful disguise by the extraterrestrial intelligence that will be sooner or later found by professor Okulov!) That’s why Okulov wants to choose among the available crater descriptions the largest set that would satisfy his theory.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line has an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 2000</span>) — the number of discovered craters. The next <span class=\"tex-span\"><i>n</i></span> lines contain crater descriptions in the "<span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>" format, where <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> is the coordinate of the center of the crater on the moon robot’s path, <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span> is the radius of the crater. All the numbers <span class=\"tex-span\"><i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span> are positive integers not exceeding <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. No two craters coincide.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the number of craters in the required largest set. In the next line output space-separated numbers of craters that this set consists of. The craters are numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span> in the order in which they were given in the input data. The numbers may be output in any order. If the result is not unique, output any.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />1 1<br />2 2<br />4 1<br />5 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br />1 2 4<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=school\" class=\"tag notice\" style=\"text-decoration: none;\">school</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=team\" class=\"tag notice\" style=\"text-decoration: none;\">team</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+9</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/786#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/786#comments\">\n 5\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div 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Cubical Planet"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Cubical Planet</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>You can find anything whatsoever in our Galaxy! A cubical planet goes round an icosahedral star. Let us introduce a system of axes so that the edges of the cubical planet are parallel to the coordinate axes and two opposite vertices lay in the points <span class=\"tex-span\">(0, 0, 0)</span> and <span class=\"tex-span\">(1, 1, 1)</span>. Two flies live on the planet. At the moment they are sitting on two different vertices of the cubical planet. Your task is to determine whether they see each other or not. The flies see each other when the vertices they occupy lie on the same face of the cube.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three space-separated integers (<span class=\"tex-span\">0</span> or <span class=\"tex-span\">1</span>) — the coordinates of the first fly, the second line analogously contains the coordinates of the second fly.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output \"YES\" (without quotes) if the flies see each other. Otherwise, output \"NO\".</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>0 0 0<br/>0 1 0<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 1 0<br/>0 1 0<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>0 0 0<br/>1 1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"60f74c28b142411f8602776c4c4f3e40\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='60f74c28b142411f8602776c4c4f3e40'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Mathematics including integration, differential equations, etc\">\r\n math\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1100\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='60f74c28b142411f8602776c4c4f3e40'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"177\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='60f74c28b142411f8602776c4c4f3e40'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"177\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/39\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/39/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/39/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/39/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/39/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/39/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange 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value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_0ff202f1149f2a35365a5f9e67041a18b71dad6b\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Cubical Planet</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>You can find anything whatsoever in our Galaxy! A cubical planet goes round an icosahedral star. Let us introduce a system of axes so that the edges of the cubical planet are parallel to the coordinate axes and two opposite vertices lay in the points <span class=\"tex-span\">(0, 0, 0)</span> and <span class=\"tex-span\">(1, 1, 1)</span>. Two flies live on the planet. At the moment they are sitting on two different vertices of the cubical planet. Your task is to determine whether they see each other or not. The flies see each other when the vertices they occupy lie on the same face of the cube.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three space-separated integers (<span class=\"tex-span\">0</span> or <span class=\"tex-span\">1</span>) — the coordinates of the first fly, the second line analogously contains the coordinates of the second fly.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output "YES" (without quotes) if the flies see each other. Otherwise, output "NO".</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>0 0 0<br />0 1 0<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 1 0<br />0 1 0<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>0 0 0<br />1 1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, 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src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/786#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/786#comments\">\n 5\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-796\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 0.5em;left:4px;display: none;\">\r\n <input type=\"radio\" name=\"locale\" value=\"en\"><span style=\"font-size: 1.2rem;position: relative; bottom: 3px;\">In English</span>\r\n <input style=\"margin-left:1em\" type=\"radio\" name=\"locale\" value=\"ru\"><span style=\"font-size: 1.2rem;position: relative; bottom: 3px;\">In Russian</span>\r\n </div>\r\n <textarea data-drafts-id=\"CommentReplyFrame\" class=\"wysiwyg\" name=\"editContent\" rows=\"20\" style=\"width:99%;\"></textarea>\r\n <div class=\"error error__content\"></div>\r\n <div style=\"text-align:center;\">\r\n <input type=\"button\" name=\"preview\" style=\"padding: 0.25em 1em; margin-top: 1em; min-width: 6.5em;\" value=\"Preview\"/>\r\n <input 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What Has Dirichlet Got to Do with That?"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. What Has Dirichlet Got to Do with That?</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>You all know the Dirichlet principle, the point of which is that if <span class=\"tex-span\"><i>n</i></span> boxes have no less than <span class=\"tex-span\"><i>n</i> + 1</span> items, that leads to the existence of a box in which there are at least two items.</p><p>Having heard of that principle, but having not mastered the technique of logical thinking, 8 year olds Stas and Masha invented a game. There are <span class=\"tex-span\"><i>a</i></span> different boxes and <span class=\"tex-span\"><i>b</i></span> different items, and each turn a player can either add a new box or a new item. The player, after whose turn the number of ways of putting <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes becomes no less then a certain given number <span class=\"tex-span\"><i>n</i></span>, loses. All the boxes and items are considered to be different. Boxes may remain empty.</p><p>Who loses if both players play optimally and Stas's turn is first?</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The only input line has three integers <span class=\"tex-span\"><i>a</i>, <i>b</i>, <i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>a</i> ≤ 10000</span>, <span class=\"tex-span\">1 ≤ <i>b</i> ≤ 30</span>, <span class=\"tex-span\">2 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">9</sup></span>) — the initial number of the boxes, the number of the items and the number which constrains the number of ways, respectively. Guaranteed that the initial number of ways is strictly less than <span class=\"tex-span\"><i>n</i></span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output \"Stas\" if Masha wins. Output \"Masha\" if Stas wins. In case of a draw, output \"Missing\".</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 10<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Masha<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5 5 16808<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Masha<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 1 4<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Stas<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 4 10<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Missing<br/></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>In the second example the initial number of ways is equal to <span class=\"tex-span\">3125</span>. </p><ul> <li> If Stas increases the number of boxes, he will lose, as Masha may increase the number of boxes once more during her turn. After that any Stas's move will lead to defeat. </li><li> But if Stas increases the number of items, then any Masha's move will be losing. </li></ul></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"3c5c4de8045eef31e395c19dcb1e1469\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='3c5c4de8045eef31e395c19dcb1e1469'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Dynamic programming\">\r\n dp\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Games, Sprague–Grundy theorem\">\r\n games\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2000\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='3c5c4de8045eef31e395c19dcb1e1469'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"178\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='3c5c4de8045eef31e395c19dcb1e1469'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"178\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/39\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/39/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/39/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/39/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/39/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/39/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n 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(!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"E\" data-uuid=\"ps_2946367956e88c7a3eac7cdfd21efe7de53e1092\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. What Has Dirichlet Got to Do with That?</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>You all know the Dirichlet principle, the point of which is that if <span class=\"tex-span\"><i>n</i></span> boxes have no less than <span class=\"tex-span\"><i>n</i> + 1</span> items, that leads to the existence of a box in which there are at least two items.</p><p>Having heard of that principle, but having not mastered the technique of logical thinking, 8 year olds Stas and Masha invented a game. There are <span class=\"tex-span\"><i>a</i></span> different boxes and <span class=\"tex-span\"><i>b</i></span> different items, and each turn a player can either add a new box or a new item. The player, after whose turn the number of ways of putting <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes becomes no less then a certain given number <span class=\"tex-span\"><i>n</i></span>, loses. All the boxes and items are considered to be different. Boxes may remain empty.</p><p>Who loses if both players play optimally and Stas's turn is first?</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The only input line has three integers <span class=\"tex-span\"><i>a</i>, <i>b</i>, <i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>a</i> ≤ 10000</span>, <span class=\"tex-span\">1 ≤ <i>b</i> ≤ 30</span>, <span class=\"tex-span\">2 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">9</sup></span>) — the initial number of the boxes, the number of the items and the number which constrains the number of ways, respectively. Guaranteed that the initial number of ways is strictly less than <span class=\"tex-span\"><i>n</i></span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output "Stas" if Masha wins. Output "Masha" if Stas wins. In case of a draw, output "Missing".</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 10<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Masha<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5 5 16808<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Masha<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 1 4<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Stas<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 4 10<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>Missing<br /></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>In the second example the initial number of ways is equal to <span class=\"tex-span\">3125</span>. </p><ul> <li> If Stas increases the number of boxes, he will lose, as Masha may increase the number of boxes once more during her turn. 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, 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src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/786#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/786#comments\">\n 5\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-796\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 0.5em;left:4px;display: none;\">\r\n <input type=\"radio\" name=\"locale\" value=\"en\"><span style=\"font-size: 1.2rem;position: relative; bottom: 3px;\">In English</span>\r\n <input style=\"margin-left:1em\" type=\"radio\" name=\"locale\" value=\"ru\"><span style=\"font-size: 1.2rem;position: relative; bottom: 3px;\">In Russian</span>\r\n </div>\r\n <textarea data-drafts-id=\"CommentReplyFrame\" class=\"wysiwyg\" name=\"editContent\" rows=\"20\" style=\"width:99%;\"></textarea>\r\n <div class=\"error error__content\"></div>\r\n <div style=\"text-align:center;\">\r\n <input type=\"button\" name=\"preview\" style=\"padding: 0.25em 1em; margin-top: 1em; min-width: 6.5em;\" value=\"Preview\"/>\r\n <input 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Pacifist frogs"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">F. Pacifist frogs</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Thumbelina has had an accident. She has found herself on a little island in the middle of a swamp and wants to get to the shore very much.</p><p>One can get to the shore only by hills that are situated along a straight line that connects the little island with the shore. Let us assume that the hills are numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span> and the number of a hill is equal to the distance in meters between it and the island. The distance between the <span class=\"tex-span\"><i>n</i></span>-th hill and the shore is also <span class=\"tex-span\">1</span> meter.</p><p>Thumbelina is too small to make such jumps. Fortunately, a family of frogs living in the swamp suggests to help her. Each frog agrees to give Thumbelina a ride but Thumbelina should choose only one frog. Each frog has a certain jump length. If Thumbelina agrees to accept help from a frog whose jump length is <span class=\"tex-span\"><i>d</i></span>, the frog will jump from the island on the hill <span class=\"tex-span\"><i>d</i></span>, then — on the hill <span class=\"tex-span\">2<i>d</i></span>, then <span class=\"tex-span\">3<i>d</i></span> and so on until they get to the shore (i.e. find itself beyond the hill <span class=\"tex-span\"><i>n</i></span>).</p><p>However, there is one more problem: mosquitoes also live in the swamp. At the moment they have a siesta, and they are having a nap on some hills. If the frog jumps on a hill with a mosquito the frog will smash it. The frogs Thumbelina has met are pacifists, so they will find the death of each mosquito very much sad. Help Thumbelina choose a frog that will bring her to the shore and smash as small number of mosquitoes as possible.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">9</sup></span>, <span class=\"tex-span\">1 ≤ <i>m</i>, <i>k</i> ≤ 100</span>) — the number of hills, frogs and mosquitoes respectively. The second line contains <span class=\"tex-span\"><i>m</i></span> integers <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>d</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>) — the lengths of the frogs’ jumps. The third line contains <span class=\"tex-span\"><i>k</i></span> integers — the numbers of the hills on which each mosquito is sleeping. No more than one mosquito can sleep on each hill. The numbers in the lines are separated by single spaces.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the number of frogs that smash the minimal number of mosquitoes, in the second line — their numbers in increasing order separated by spaces. The frogs are numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>m</i></span> in the order of the jump length given in the input data.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5 3 5<br/>2 3 4<br/>1 2 3 4 5<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/>2 3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1000000000 2 3<br/>2 5<br/>999999995 999999998 999999996<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/>2<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"f33290ae0834f18258e6322522fdabb9\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - F - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - F - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='f33290ae0834f18258e6322522fdabb9'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1300\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='f33290ae0834f18258e6322522fdabb9'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"179\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='f33290ae0834f18258e6322522fdabb9'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"179\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/39\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/39/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/39/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/39/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/39/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/39/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || 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value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"F\" data-uuid=\"ps_719593f0b45b10605b42a5b76628fcbd1e0f55b3\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">F. Pacifist frogs</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Thumbelina has had an accident. She has found herself on a little island in the middle of a swamp and wants to get to the shore very much.</p><p>One can get to the shore only by hills that are situated along a straight line that connects the little island with the shore. Let us assume that the hills are numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span> and the number of a hill is equal to the distance in meters between it and the island. The distance between the <span class=\"tex-span\"><i>n</i></span>-th hill and the shore is also <span class=\"tex-span\">1</span> meter.</p><p>Thumbelina is too small to make such jumps. Fortunately, a family of frogs living in the swamp suggests to help her. Each frog agrees to give Thumbelina a ride but Thumbelina should choose only one frog. Each frog has a certain jump length. If Thumbelina agrees to accept help from a frog whose jump length is <span class=\"tex-span\"><i>d</i></span>, the frog will jump from the island on the hill <span class=\"tex-span\"><i>d</i></span>, then — on the hill <span class=\"tex-span\">2<i>d</i></span>, then <span class=\"tex-span\">3<i>d</i></span> and so on until they get to the shore (i.e. find itself beyond the hill <span class=\"tex-span\"><i>n</i></span>).</p><p>However, there is one more problem: mosquitoes also live in the swamp. At the moment they have a siesta, and they are having a nap on some hills. If the frog jumps on a hill with a mosquito the frog will smash it. The frogs Thumbelina has met are pacifists, so they will find the death of each mosquito very much sad. Help Thumbelina choose a frog that will bring her to the shore and smash as small number of mosquitoes as possible.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">9</sup></span>, <span class=\"tex-span\">1 ≤ <i>m</i>, <i>k</i> ≤ 100</span>) — the number of hills, frogs and mosquitoes respectively. The second line contains <span class=\"tex-span\"><i>m</i></span> integers <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>d</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>) — the lengths of the frogs’ jumps. The third line contains <span class=\"tex-span\"><i>k</i></span> integers — the numbers of the hills on which each mosquito is sleeping. No more than one mosquito can sleep on each hill. The numbers in the lines are separated by single spaces.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the number of frogs that smash the minimal number of mosquitoes, in the second line — their numbers in increasing order separated by spaces. The frogs are numbered from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>m</i></span> in the order of the jump length given in the input data.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5 3 5<br />2 3 4<br />1 2 3 4 5<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br />2 3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1000000000 2 3<br />2 5<br />999999995 999999998 999999996<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br />2<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=F]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n </label>\r\n </div>\r\n <div style=\"padding: 0 1em 1em 1em;text-align:right;\">\r\n <input style=\"height:1.65em;padding:0 0.75em;\" type=\"submit\" value=\"Find\"/>\r\n </div>\r\n </form>\r\n </div>\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".handleBox\").autocomplete(\"/data/handles\", {\r\n delay: 200,\r\n width: 200,\r\n selectFirst: false,\r\n matchContains: true,\r\n minChars: 3\r\n });\r\n $(\".handleForm\").attr(\"autocomplete\", \"off\").submit(function () {\r\n var link = \"/profile/userHandle\".replace(\r\n \"userHandle\", $(this).find(\".handleBox\").val()\r\n );\r\n window.location = link;\r\n return false;\r\n });\r\n });\n </script>\n\r\n\r\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Recent actions\n <div class=\"top-links\">\n </div>\n </div>\n <div class=\"recent-actions\">\r\n <ul>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a href=\"/blog/entry/121171\">An Interesting Tree Problem</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/.Danet\" title=\"Expert .Danet\" class=\"rated-user user-blue\">.Danet</a> →\r\n <a href=\"/blog/entry/121172\">[TLE on pretest1]</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/sszcdjr\" title=\"Master sszcdjr\" class=\"rated-user user-orange\">sszcdjr</a> →\r\n <a href=\"/blog/entry/119859\">Codeforces Round 896 (Div. 1, Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/119880\">It's Happening! Meta Hacker Cup 2023 Schedule</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/DaviddeGea1\" title=\"Expert DaviddeGea1\" class=\"rated-user user-blue\">DaviddeGea1</a> →\r\n <a href=\"/blog/entry/70917\">Number of ways of dividing an array into 2 parts such that sum of each part is > k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a> →\r\n <a href=\"/blog/entry/74245\">Questions and doubts regarding Aliens DP trick</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/cgy4ever\" title=\"International Grandmaster cgy4ever\" class=\"rated-user user-red\">cgy4ever</a> →\r\n <a href=\"/blog/entry/8192\">Codeforces Round #190 — Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/hocky\" title=\"Candidate Master hocky\" class=\"rated-user user-violet\">hocky</a> →\r\n <a href=\"/blog/entry/95323\">FBHC wuining uw Day? Incwease uw stacc size! (ㅅ´ ˘ `)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/liouzhou_101\" title=\"International Master liouzhou_101\" class=\"rated-user user-orange\">liouzhou_101</a> →\r\n <a href=\"/blog/entry/87598\">Editorial of Codeforces Round #700</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/yeon_gist\" title=\"Newbie yeon_gist\" class=\"rated-user user-gray\">yeon_gist</a> →\r\n <a href=\"/blog/entry/121170\">plusMinusPermutation computing error</a>\r\n <img alt=\"Text created or updated\" title=\"Text created or updated\" src=\"//codeforces.org/s/81027/images/icons/x-update-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/altforminuscontribution\" title=\"Newbie altforminuscontribution\" class=\"rated-user user-gray\">altforminuscontribution</a> →\r\n <a href=\"/blog/entry/121162\">My screen get unexpectedly big, what should I do</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/atcoder_official\" title=\"Unrated, atcoder_official\" class=\"rated-user user-black\">atcoder_official</a> →\r\n <a href=\"/blog/entry/121120\">We will hold UNIQUE VISION Programming Contest 2023 Autumn(AtCoder Beginner Contest 323)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/YouStill_DontKnowMeYet\" title=\"Candidate Master YouStill_DontKnowMeYet\" class=\"rated-user user-violet\">YouStill_DontKnowMeYet</a> →\r\n <a href=\"/blog/entry/117659\">[GYM] Al-Baath Collegiate Programming Contest 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/ankancool\" title=\"Expert ankancool\" class=\"rated-user user-blue\">ankancool</a> →\r\n <a href=\"/blog/entry/121136\">Invitation to AstroByte 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/GeZhiyuan\" title=\"Grandmaster GeZhiyuan\" class=\"rated-user user-red\">GeZhiyuan</a> →\r\n <a href=\"/blog/entry/120943\">Codeforces Round 901 (Div. 1, Div. 2) Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a> →\r\n <a href=\"/blog/entry/120772\">PSA: Increase your stack size before the Meta Hacker Cup, here's how</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/dino_merlin\" title=\"Expert dino_merlin\" class=\"rated-user user-blue\">dino_merlin</a> →\r\n <a href=\"/blog/entry/121145\">Intuitive approach for CEOI Kangaroo?</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/icecuber\" title=\"Grandmaster icecuber\" class=\"rated-user user-red\">icecuber</a> →\r\n <a href=\"/blog/entry/70018\">CSES DP section editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bn00b\" title=\"Newbie Bn00b\" class=\"rated-user user-gray\">Bn00b</a> →\r\n <a href=\"/blog/entry/98820\">[FEATURE REQUEST : ATCODER] TOPICS TAGS AND SORTING BY SOLVE COUNT</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a> →\r\n <a href=\"/blog/entry/121163\">AtCoder Regular Contest 166 Announcement</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/windva\" title=\"Grandmaster windva\" class=\"rated-user user-red\">windva</a> →\r\n <a href=\"/blog/entry/120644\">Codeforces Round 899 (Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Misa-Misa\" title=\"Expert Misa-Misa\" class=\"rated-user user-blue\">Misa-Misa</a> →\r\n <a href=\"/blog/entry/121157\">Someone please help me understand this.</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, 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href=\"#\" class=\"topic-vote-up-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+9</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/786#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/786#comments\">\n 5\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div 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Inverse Function"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">G. Inverse Function</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>5 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Petya wrote a programme on C++ that calculated a very interesting function <span class=\"tex-span\"><i>f</i>(<i>n</i>)</span>. Petya ran the program with a certain value of <span class=\"tex-span\"><i>n</i></span> and went to the kitchen to have some tea. The history has no records concerning how long the program had been working. By the time Petya returned, it had completed the calculations and had the result. However while Petya was drinking tea, a sly virus managed to destroy the input file so that Petya can't figure out for which value of <span class=\"tex-span\"><i>n</i></span> the program was run. Help Petya, carry out the inverse function!</p><p>Mostly, the program consists of a function in C++ with the following simplified syntax:</p><ul> <li> <span class=\"tex-span\"><i>function</i></span> ::= int f(int n) {<span class=\"tex-span\"><i>operatorSequence</i></span>}</li><li> <span class=\"tex-span\"><i>operatorSequence</i></span> ::= <span class=\"tex-span\"><i>operator</i> | <i>operator</i> <i>operatorSequence</i></span></li><li> <span class=\"tex-span\"><i>operator</i></span> ::= return <span class=\"tex-span\"><i>arithmExpr</i></span>; <span class=\"tex-span\">|</span> if (<span class=\"tex-span\"><i>logicalExpr</i></span>) return <span class=\"tex-span\"><i>arithmExpr</i></span>;</li><li> <span class=\"tex-span\"><i>logicalExpr</i></span> ::= <span class=\"tex-span\"><i>arithmExpr</i> > <i>arithmExpr</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>arithmExpr</i> < <i>arithmExpr</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>arithmExpr</i></span> == <span class=\"tex-span\"><i>arithmExpr</i></span></li><li> <span class=\"tex-span\"><i>arithmExpr</i></span> ::= <span class=\"tex-span\"><i>sum</i></span></li><li> <span class=\"tex-span\"><i>sum</i></span> ::= <span class=\"tex-span\"><i>product</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>sum</i> + <i>product</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>sum</i> - <i>product</i></span></li><li> <span class=\"tex-span\"><i>product</i></span> ::= <span class=\"tex-span\"><i>multiplier</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>product</i> * <i>multiplier</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>product</i> / <i>multiplier</i></span></li><li> <span class=\"tex-span\"><i>multiplier</i></span> ::= n <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>number</i></span> <span class=\"tex-span\">|</span> f(<span class=\"tex-span\"><i>arithmExpr</i></span>)</li><li> <span class=\"tex-span\"><i>number</i></span> ::= <span class=\"tex-span\">0|1|2|... |32767</span> </li></ul><p>The whitespaces in a <span class=\"tex-span\"><i>operatorSequence</i></span> are optional.</p><p>Thus, we have a function, in which body there are two kinds of operators. There is the operator \"return <span class=\"tex-span\"><i>arithmExpr</i></span>;\" that returns the value of the expression as the value of the function, and there is the conditional operator \"if (<span class=\"tex-span\"><i>logicalExpr</i></span>) return <span class=\"tex-span\"><i>arithmExpr</i></span>;\" that returns the value of the arithmetical expression when and only when the logical expression is true. Guaranteed that no other constructions of C++ language — cycles, assignment operators, nested conditional operators etc, and other variables except the <span class=\"tex-span\"><i>n</i></span> parameter are used in the function. All the constants are integers in the interval <span class=\"tex-span\">[0..32767]</span>.</p><p>The operators are performed sequentially. After the function has returned a value other operators in the sequence are not performed. Arithmetical expressions are performed taking into consideration the standard priority of the operations. It means that first all the products that are part of the sum are calculated. During the calculation of the products the operations of multiplying and division are performed from the left to the right. Then the summands are summed, and the addition and the subtraction are also performed from the left to the right. Operations \">\" (more), \"<\" (less) and \"==\" (equals) also have standard meanings.</p><p>Now you've got to pay close attention! The program is compiled with the help of <span class=\"tex-span\">15</span>-bit Berland C++ compiler invented by a Berland company BerSoft, that's why arithmetical operations are performed in a non-standard way. Addition, subtraction and multiplication are performed modulo <span class=\"tex-span\">32768</span> (if the result of subtraction is negative, then <span class=\"tex-span\">32768</span> is added to it until the number belongs to the interval <span class=\"tex-span\">[0..32767]</span>). Division \"/\" is a usual integer division where the remainder is omitted.</p><p>Examples of arithmetical operations: </p><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/8ad212e9d903275cafc1b8d675eb4e4dca7d7f9b.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/></center><p>Guaranteed that for all values of <span class=\"tex-span\"><i>n</i></span> from <span class=\"tex-span\">0</span> to <span class=\"tex-span\">32767</span> the given function is performed correctly. That means that:</p><p>1. Division by <span class=\"tex-span\">0</span> never occures.</p><p>2. When performing a function for the value <span class=\"tex-span\"><i>n</i> = <i>N</i></span> recursive calls of the function <span class=\"tex-span\"><i>f</i></span> may occur only for the parameter value of <span class=\"tex-span\">0, 1, ..., <i>N</i> - 1</span>. Consequently, the program never has an infinite recursion.</p><p>3. As the result of the sequence of the operators, the function always returns a value.</p><p>We have to mention that due to all the limitations the value returned by the function <span class=\"tex-span\"><i>f</i></span> is independent from either global variables or the order of performing the calculations of arithmetical expressions as part of the logical one, or from anything else except the value of <span class=\"tex-span\"><i>n</i></span> parameter. That's why the <span class=\"tex-span\"><i>f</i></span> function can be regarded as a function in its mathematical sense, i.e. as a unique correspondence between any value of <span class=\"tex-span\"><i>n</i></span> from the interval <span class=\"tex-span\">[0..32767]</span> and a value of <span class=\"tex-span\"><i>f</i>(<i>n</i>)</span> from the same interval.</p><p>Given the value of <span class=\"tex-span\"><i>f</i>(<i>n</i>)</span>, and you should find <span class=\"tex-span\"><i>n</i></span>. If the suitable <span class=\"tex-span\"><i>n</i></span> value is not unique, you should find the maximal one (from the interval <span class=\"tex-span\">[0..32767]</span>).</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line has an integer <span class=\"tex-span\"><i>f</i>(<i>n</i>)</span> from the interval <span class=\"tex-span\">[0..32767]</span>. The next lines have the description of the function <span class=\"tex-span\"><i>f</i></span>. In the description can be found extra spaces and line breaks (see the examples) which, of course, can’t break key words int, if, return and numbers. The size of input data can’t exceed <span class=\"tex-span\">100</span> bytes.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a single number — the answer to the problem. If there’s no answer, output \"-1\" (without quotes).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>17<br/>int f(int n)<br/>{<br/>if (n < 100) return 17;<br/>if (n > 99) return 27;<br/>}<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>99<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>13<br/>int f(int n)<br/>{<br/>if (n == 0) return 0;<br/>return f(n - 1) + 1;<br/>}<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>13</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>144<br/>int f(int n)<br/>{<br/>if (n == 0) return 0;<br/>if (n == 1) return n;<br/>return f(n - 1) + f(n - 2);<br/>}</pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>24588<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"f634f2ec5d916ae5108a2a9714e0ba89\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - G - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - G - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='f634f2ec5d916ae5108a2a9714e0ba89'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2400\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='f634f2ec5d916ae5108a2a9714e0ba89'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"180\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='f634f2ec5d916ae5108a2a9714e0ba89'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"180\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/39\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/39/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/39/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/39/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/39/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/39/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange 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node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"G\" data-uuid=\"ps_c12da8506afc977d31de9f90c66511883d6b3923\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">G. Inverse Function</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>5 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Petya wrote a programme on C++ that calculated a very interesting function <span class=\"tex-span\"><i>f</i>(<i>n</i>)</span>. Petya ran the program with a certain value of <span class=\"tex-span\"><i>n</i></span> and went to the kitchen to have some tea. The history has no records concerning how long the program had been working. By the time Petya returned, it had completed the calculations and had the result. However while Petya was drinking tea, a sly virus managed to destroy the input file so that Petya can't figure out for which value of <span class=\"tex-span\"><i>n</i></span> the program was run. Help Petya, carry out the inverse function!</p><p>Mostly, the program consists of a function in C++ with the following simplified syntax:</p><ul> <li> <span class=\"tex-span\"><i>function</i></span> ::= int f(int n) {<span class=\"tex-span\"><i>operatorSequence</i></span>}</li><li> <span class=\"tex-span\"><i>operatorSequence</i></span> ::= <span class=\"tex-span\"><i>operator</i> | <i>operator</i> <i>operatorSequence</i></span></li><li> <span class=\"tex-span\"><i>operator</i></span> ::= return <span class=\"tex-span\"><i>arithmExpr</i></span>; <span class=\"tex-span\">|</span> if (<span class=\"tex-span\"><i>logicalExpr</i></span>) return <span class=\"tex-span\"><i>arithmExpr</i></span>;</li><li> <span class=\"tex-span\"><i>logicalExpr</i></span> ::= <span class=\"tex-span\"><i>arithmExpr</i> > <i>arithmExpr</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>arithmExpr</i> < <i>arithmExpr</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>arithmExpr</i></span> == <span class=\"tex-span\"><i>arithmExpr</i></span></li><li> <span class=\"tex-span\"><i>arithmExpr</i></span> ::= <span class=\"tex-span\"><i>sum</i></span></li><li> <span class=\"tex-span\"><i>sum</i></span> ::= <span class=\"tex-span\"><i>product</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>sum</i> + <i>product</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>sum</i> - <i>product</i></span></li><li> <span class=\"tex-span\"><i>product</i></span> ::= <span class=\"tex-span\"><i>multiplier</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>product</i> * <i>multiplier</i></span> <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>product</i> / <i>multiplier</i></span></li><li> <span class=\"tex-span\"><i>multiplier</i></span> ::= n <span class=\"tex-span\">|</span> <span class=\"tex-span\"><i>number</i></span> <span class=\"tex-span\">|</span> f(<span class=\"tex-span\"><i>arithmExpr</i></span>)</li><li> <span class=\"tex-span\"><i>number</i></span> ::= <span class=\"tex-span\">0|1|2|... |32767</span> </li></ul><p>The whitespaces in a <span class=\"tex-span\"><i>operatorSequence</i></span> are optional.</p><p>Thus, we have a function, in which body there are two kinds of operators. There is the operator "return <span class=\"tex-span\"><i>arithmExpr</i></span>;" that returns the value of the expression as the value of the function, and there is the conditional operator "if (<span class=\"tex-span\"><i>logicalExpr</i></span>) return <span class=\"tex-span\"><i>arithmExpr</i></span>;" that returns the value of the arithmetical expression when and only when the logical expression is true. Guaranteed that no other constructions of C++ language — cycles, assignment operators, nested conditional operators etc, and other variables except the <span class=\"tex-span\"><i>n</i></span> parameter are used in the function. All the constants are integers in the interval <span class=\"tex-span\">[0..32767]</span>.</p><p>The operators are performed sequentially. After the function has returned a value other operators in the sequence are not performed. Arithmetical expressions are performed taking into consideration the standard priority of the operations. It means that first all the products that are part of the sum are calculated. During the calculation of the products the operations of multiplying and division are performed from the left to the right. Then the summands are summed, and the addition and the subtraction are also performed from the left to the right. Operations ">" (more), "<" (less) and "==" (equals) also have standard meanings.</p><p>Now you've got to pay close attention! The program is compiled with the help of <span class=\"tex-span\">15</span>-bit Berland C++ compiler invented by a Berland company BerSoft, that's why arithmetical operations are performed in a non-standard way. Addition, subtraction and multiplication are performed modulo <span class=\"tex-span\">32768</span> (if the result of subtraction is negative, then <span class=\"tex-span\">32768</span> is added to it until the number belongs to the interval <span class=\"tex-span\">[0..32767]</span>). Division "/" is a usual integer division where the remainder is omitted.</p><p>Examples of arithmetical operations: </p><center class=\"tex-equation\"><img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/8ad212e9d903275cafc1b8d675eb4e4dca7d7f9b.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center><p>Guaranteed that for all values of <span class=\"tex-span\"><i>n</i></span> from <span class=\"tex-span\">0</span> to <span class=\"tex-span\">32767</span> the given function is performed correctly. That means that:</p><p>1. Division by <span class=\"tex-span\">0</span> never occures.</p><p>2. When performing a function for the value <span class=\"tex-span\"><i>n</i> = <i>N</i></span> recursive calls of the function <span class=\"tex-span\"><i>f</i></span> may occur only for the parameter value of <span class=\"tex-span\">0, 1, ..., <i>N</i> - 1</span>. Consequently, the program never has an infinite recursion.</p><p>3. As the result of the sequence of the operators, the function always returns a value.</p><p>We have to mention that due to all the limitations the value returned by the function <span class=\"tex-span\"><i>f</i></span> is independent from either global variables or the order of performing the calculations of arithmetical expressions as part of the logical one, or from anything else except the value of <span class=\"tex-span\"><i>n</i></span> parameter. That's why the <span class=\"tex-span\"><i>f</i></span> function can be regarded as a function in its mathematical sense, i.e. as a unique correspondence between any value of <span class=\"tex-span\"><i>n</i></span> from the interval <span class=\"tex-span\">[0..32767]</span> and a value of <span class=\"tex-span\"><i>f</i>(<i>n</i>)</span> from the same interval.</p><p>Given the value of <span class=\"tex-span\"><i>f</i>(<i>n</i>)</span>, and you should find <span class=\"tex-span\"><i>n</i></span>. If the suitable <span class=\"tex-span\"><i>n</i></span> value is not unique, you should find the maximal one (from the interval <span class=\"tex-span\">[0..32767]</span>).</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line has an integer <span class=\"tex-span\"><i>f</i>(<i>n</i>)</span> from the interval <span class=\"tex-span\">[0..32767]</span>. The next lines have the description of the function <span class=\"tex-span\"><i>f</i></span>. In the description can be found extra spaces and line breaks (see the examples) which, of course, can’t break key words int, if, return and numbers. The size of input data can’t exceed <span class=\"tex-span\">100</span> bytes.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a single number — the answer to the problem. If there’s no answer, output "-1" (without quotes).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>17<br />int f(int n)<br />{<br />if (n < 100) return 17;<br />if (n > 99) return 27;<br />}<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>99<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>13<br />int f(int n)<br />{<br />if (n == 0) return 0;<br />return f(n - 1) + 1;<br />}<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>13</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>144<br />int f(int n)<br />{<br />if (n == 0) return 0;<br />if (n == 1) return n;<br />return f(n - 1) + f(n - 2);<br />}</pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>24588<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, 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}\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div 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Multiplication Table"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">H. Multiplication Table</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Petya studies positional notations. He has already learned to add and subtract numbers in the systems of notations with different radices and has moved on to a more complicated action — multiplication. To multiply large numbers one has to learn the multiplication table. Unfortunately, in the second grade students learn only the multiplication table of decimals (and some students even learn it in the first grade). Help Petya make a multiplication table for numbers in the system of notations with the radix <span class=\"tex-span\"><i>k</i></span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains a single integer <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">2 ≤ <i>k</i> ≤ 10</span>) — the radix of the system.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the multiplication table for the system of notations with the radix <span class=\"tex-span\"><i>k</i></span>. The table must contain <span class=\"tex-span\"><i>k</i> - 1</span> rows and <span class=\"tex-span\"><i>k</i> - 1</span> columns. The element on the crossing of the <span class=\"tex-span\"><i>i</i></span>-th row and the <span class=\"tex-span\"><i>j</i></span>-th column is equal to the product of <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> in the system of notations with the radix <span class=\"tex-span\"><i>k</i></span>. Each line may have any number of spaces between the numbers (the extra spaces in the samples are put for clarity).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>10<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 2 3 4 5 6 7 8 9<br/>2 4 6 8 10 12 14 16 18<br/>3 6 9 12 15 18 21 24 27<br/>4 8 12 16 20 24 28 32 36<br/>5 10 15 20 25 30 35 40 45<br/>6 12 18 24 30 36 42 48 54<br/>7 14 21 28 35 42 49 56 63<br/>8 16 24 32 40 48 56 64 72<br/>9 18 27 36 45 54 63 72 81<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 2<br/>2 11</pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"fc9d7791dcb29901adef2a68abd19abd\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - H - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - H - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='fc9d7791dcb29901adef2a68abd19abd'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1300\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='fc9d7791dcb29901adef2a68abd19abd'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"181\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='fc9d7791dcb29901adef2a68abd19abd'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"181\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/39\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/39/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/39/my\">My Submissions</a></li>\r\n <li><a\r\n 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value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"H\" data-uuid=\"ps_344d5b06b1dd628b585c396129da436e80592ac3\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">H. Multiplication Table</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Petya studies positional notations. He has already learned to add and subtract numbers in the systems of notations with different radices and has moved on to a more complicated action — multiplication. To multiply large numbers one has to learn the multiplication table. Unfortunately, in the second grade students learn only the multiplication table of decimals (and some students even learn it in the first grade). Help Petya make a multiplication table for numbers in the system of notations with the radix <span class=\"tex-span\"><i>k</i></span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains a single integer <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">2 ≤ <i>k</i> ≤ 10</span>) — the radix of the system.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output the multiplication table for the system of notations with the radix <span class=\"tex-span\"><i>k</i></span>. The table must contain <span class=\"tex-span\"><i>k</i> - 1</span> rows and <span class=\"tex-span\"><i>k</i> - 1</span> columns. The element on the crossing of the <span class=\"tex-span\"><i>i</i></span>-th row and the <span class=\"tex-span\"><i>j</i></span>-th column is equal to the product of <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> in the system of notations with the radix <span class=\"tex-span\"><i>k</i></span>. Each line may have any number of spaces between the numbers (the extra spaces in the samples are put for clarity).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>10<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 2 3 4 5 6 7 8 9<br />2 4 6 8 10 12 14 16 18<br />3 6 9 12 15 18 21 24 27<br />4 8 12 16 20 24 28 32 36<br />5 10 15 20 25 30 35 40 45<br />6 12 18 24 30 36 42 48 54<br />7 14 21 28 35 42 49 56 63<br />8 16 24 32 40 48 56 64 72<br />9 18 27 36 45 54 63 72 81<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 2<br />2 11</pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=H]\");\r\n let uuid = 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, 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href=\"#\" class=\"topic-vote-up-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+9</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/786#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/786#comments\">\n 5\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div 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Tram"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">I. Tram</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>In a Berland city S*** there is a tram engine house and only one tram. Three people work in the house — the tram driver, the conductor and the head of the engine house. The tram used to leave the engine house every morning and drove along his loop route. The tram needed exactly <span class=\"tex-span\"><i>c</i></span> minutes to complete the route. The head of the engine house controlled the tram’s movement, going outside every <span class=\"tex-span\"><i>c</i></span> minutes when the tram drove by the engine house, and the head left the driver without a bonus if he was even one second late.</p><p>It used to be so. Afterwards the Berland Federal Budget gave money to make more tramlines in S***, and, as it sometimes happens, the means were used as it was planned. The tramlines were rebuilt and as a result they turned into a huge network. The previous loop route may have been destroyed. S*** has <span class=\"tex-span\"><i>n</i></span> crossroads and now <span class=\"tex-span\"><i>m</i></span> tramlines that links the pairs of crossroads. The traffic in Berland is one way so the tram can move along each tramline only in one direction. There may be several tramlines between two crossroads, which go same way or opposite ways. Every tramline links two different crossroads and for each crossroad there is at least one outgoing tramline.</p><p>So, the tramlines were built but for some reason nobody gave a thought to increasing the number of trams in S***! The tram continued to ride alone but now the driver had an excellent opportunity to get rid of the unending control of the engine house head. For now due to the tramline network he could choose the route freely! Now at every crossroad the driver can arbitrarily choose the way he can go. The tram may even go to the parts of S*** from where it cannot return due to one way traffic. The driver is not afraid of the challenge: at night, when the city is asleep, he can return to the engine house safely, driving along the tramlines in the opposite direction.</p><p>The city people were rejoicing for some of the had been waiting for the tram to appear on their streets for several years. However, the driver’s behavior enraged the engine house head. Now he tries to carry out an insidious plan of installing cameras to look after the rebellious tram.</p><p>The plan goes as follows. The head of the engine house wants to install cameras at some crossroads, to choose a period of time <span class=\"tex-span\"><i>t</i></span> and every <span class=\"tex-span\"><i>t</i></span> minutes turn away from the favourite TV show to check where the tram is. Also the head of the engine house wants at all moments of time, divisible by <span class=\"tex-span\"><i>t</i></span>, and only at such moments the tram to appear on a crossroad under a camera. There must be a camera on the crossroad by the engine house to prevent possible terrorist attacks on the engine house head. Among all the possible plans the engine house head chooses the plan with the largest possible value of <span class=\"tex-span\"><i>t</i></span> (as he hates being distracted from his favourite TV show but he has to). If such a plan is not unique, pick the plan that requires the minimal possible number of cameras. Find such a plan.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">2 ≤ <i>n</i>, <i>m</i> ≤ 10<sup class=\"upper-index\">5</sup></span>) — the number of crossroads and tramlines in S*** respectively. The next <span class=\"tex-span\"><i>m</i></span> lines contain the descriptions of the tramlines in \"<span class=\"tex-span\"><i>u</i></span> <span class=\"tex-span\"><i>v</i></span>\" format, where <span class=\"tex-span\"><i>u</i></span> is the initial tramline crossroad and <span class=\"tex-span\"><i>v</i></span> is its final crossroad. The crossroads are numbered with integers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>, and the engine house is at the crossroad number <span class=\"tex-span\">1</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the value of <span class=\"tex-span\"><i>t</i></span>. In the next line output the value of <span class=\"tex-span\"><i>k</i></span> — the required number of the cameras. In the next line output space-separated numbers of the crossroads, where the cameras should be installed. Output the numbers in increasing order.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4 5<br/>1 2<br/>2 3<br/>3 4<br/>4 1<br/>1 4<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/>2<br/>1 3<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"d3180e0e9b3078c957490ee0ba708169\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - I - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - I - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='d3180e0e9b3078c957490ee0ba708169'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2500\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='d3180e0e9b3078c957490ee0ba708169'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"182\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='d3180e0e9b3078c957490ee0ba708169'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"182\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" 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}\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"I\" data-uuid=\"ps_6b26ad6a027eccd31335b0652180ddde23f777a1\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">I. Tram</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>In a Berland city S*** there is a tram engine house and only one tram. Three people work in the house — the tram driver, the conductor and the head of the engine house. The tram used to leave the engine house every morning and drove along his loop route. The tram needed exactly <span class=\"tex-span\"><i>c</i></span> minutes to complete the route. The head of the engine house controlled the tram’s movement, going outside every <span class=\"tex-span\"><i>c</i></span> minutes when the tram drove by the engine house, and the head left the driver without a bonus if he was even one second late.</p><p>It used to be so. Afterwards the Berland Federal Budget gave money to make more tramlines in S***, and, as it sometimes happens, the means were used as it was planned. The tramlines were rebuilt and as a result they turned into a huge network. The previous loop route may have been destroyed. S*** has <span class=\"tex-span\"><i>n</i></span> crossroads and now <span class=\"tex-span\"><i>m</i></span> tramlines that links the pairs of crossroads. The traffic in Berland is one way so the tram can move along each tramline only in one direction. There may be several tramlines between two crossroads, which go same way or opposite ways. Every tramline links two different crossroads and for each crossroad there is at least one outgoing tramline.</p><p>So, the tramlines were built but for some reason nobody gave a thought to increasing the number of trams in S***! The tram continued to ride alone but now the driver had an excellent opportunity to get rid of the unending control of the engine house head. For now due to the tramline network he could choose the route freely! Now at every crossroad the driver can arbitrarily choose the way he can go. The tram may even go to the parts of S*** from where it cannot return due to one way traffic. The driver is not afraid of the challenge: at night, when the city is asleep, he can return to the engine house safely, driving along the tramlines in the opposite direction.</p><p>The city people were rejoicing for some of the had been waiting for the tram to appear on their streets for several years. However, the driver’s behavior enraged the engine house head. Now he tries to carry out an insidious plan of installing cameras to look after the rebellious tram.</p><p>The plan goes as follows. The head of the engine house wants to install cameras at some crossroads, to choose a period of time <span class=\"tex-span\"><i>t</i></span> and every <span class=\"tex-span\"><i>t</i></span> minutes turn away from the favourite TV show to check where the tram is. Also the head of the engine house wants at all moments of time, divisible by <span class=\"tex-span\"><i>t</i></span>, and only at such moments the tram to appear on a crossroad under a camera. There must be a camera on the crossroad by the engine house to prevent possible terrorist attacks on the engine house head. Among all the possible plans the engine house head chooses the plan with the largest possible value of <span class=\"tex-span\"><i>t</i></span> (as he hates being distracted from his favourite TV show but he has to). If such a plan is not unique, pick the plan that requires the minimal possible number of cameras. Find such a plan.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">2 ≤ <i>n</i>, <i>m</i> ≤ 10<sup class=\"upper-index\">5</sup></span>) — the number of crossroads and tramlines in S*** respectively. The next <span class=\"tex-span\"><i>m</i></span> lines contain the descriptions of the tramlines in "<span class=\"tex-span\"><i>u</i></span> <span class=\"tex-span\"><i>v</i></span>" format, where <span class=\"tex-span\"><i>u</i></span> is the initial tramline crossroad and <span class=\"tex-span\"><i>v</i></span> is its final crossroad. The crossroads are numbered with integers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>, and the engine house is at the crossroad number <span class=\"tex-span\">1</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the value of <span class=\"tex-span\"><i>t</i></span>. In the next line output the value of <span class=\"tex-span\"><i>k</i></span> — the required number of the cameras. In the next line output space-separated numbers of the crossroads, where the cameras should be installed. Output the numbers in increasing order.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4 5<br />1 2<br />2 3<br />3 4<br />4 1<br />1 4<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br />2<br />1 3<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=I]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, 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}\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div 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Spelling Check"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">J. Spelling Check</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Petya has noticed that when he types using a keyboard, he often presses extra buttons and adds extra letters to the words. Of course, the spell-checking system underlines the words for him and he has to click every word and choose the right variant. Petya got fed up with correcting his mistakes himself, that’s why he decided to invent the function that will correct the words itself. Petya started from analyzing the case that happens to him most of the time, when all one needs is to delete one letter for the word to match a word from the dictionary. Thus, Petya faces one mini-task: he has a printed word and a word from the dictionary, and he should delete one letter from the first word to get the second one. And now the very non-trivial question that Petya faces is: which letter should he delete?</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The input data contains two strings, consisting of lower-case Latin letters. The length of each string is from <span class=\"tex-span\">1</span> to <span class=\"tex-span\">10<sup class=\"upper-index\">6</sup></span> symbols inclusive, the first string contains exactly <span class=\"tex-span\">1</span> symbol more than the second one.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the number of positions of the symbols in the first string, after the deleting of which the first string becomes identical to the second one. In the second line output space-separated positions of these symbols in increasing order. The positions are numbered starting from <span class=\"tex-span\">1</span>. If it is impossible to make the first string identical to the second string by deleting one symbol, output one number <span class=\"tex-span\">0</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>abdrakadabra<br/>abrakadabra<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/>3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>aa<br/>a<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/>1 2<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>competition<br/>codeforces<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"76a03b588fc4c6ef12c054daa46163e5\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - J - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - J - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Hashing, hashtables\">\r\n hashing\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Prefix- and Z-functions, suffix structures, Knuth–Morris–Pratt algorithm, etc\">\r\n strings\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1500\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='76a03b588fc4c6ef12c054daa46163e5'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"183\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='76a03b588fc4c6ef12c054daa46163e5'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"183\"/>\r\n <input name=\"tagName\" 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0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/39\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/39/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/39/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/39/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/39/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/39/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"J\" data-uuid=\"ps_72502eb3b295464fc904b8f97275757a6e9867d8\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">J. Spelling Check</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Petya has noticed that when he types using a keyboard, he often presses extra buttons and adds extra letters to the words. Of course, the spell-checking system underlines the words for him and he has to click every word and choose the right variant. Petya got fed up with correcting his mistakes himself, that’s why he decided to invent the function that will correct the words itself. Petya started from analyzing the case that happens to him most of the time, when all one needs is to delete one letter for the word to match a word from the dictionary. Thus, Petya faces one mini-task: he has a printed word and a word from the dictionary, and he should delete one letter from the first word to get the second one. And now the very non-trivial question that Petya faces is: which letter should he delete?</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The input data contains two strings, consisting of lower-case Latin letters. The length of each string is from <span class=\"tex-span\">1</span> to <span class=\"tex-span\">10<sup class=\"upper-index\">6</sup></span> symbols inclusive, the first string contains exactly <span class=\"tex-span\">1</span> symbol more than the second one.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line output the number of positions of the symbols in the first string, after the deleting of which the first string becomes identical to the second one. In the second line output space-separated positions of these symbols in increasing order. The positions are numbered starting from <span class=\"tex-span\">1</span>. If it is impossible to make the first string identical to the second string by deleting one symbol, output one number <span class=\"tex-span\">0</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>abdrakadabra<br />abrakadabra<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br />3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>aa<br />a<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br />1 2<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>competition<br />codeforces<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=J]\");\r\n let uuid = 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</script>\r\n\r\n\r\n<script type=\"text/javascript\">\r\n $(document).ready(function () {\r\n window.changedTests = new Set();\r\n\r\n function endsWith(string, suffix) {\r\n return string.indexOf(suffix, string.length - suffix.length) !== -1;\r\n }\r\n\r\n const inputFileDiv = $(\"div.input-file\");\r\n const inputFile = inputFileDiv.text();\r\n const outputFileDiv = $(\"div.output-file\");\r\n const outputFile = outputFileDiv.text();\r\n\r\n\r\n if (!endsWith(inputFile, \"standard input\")\r\n && !endsWith(inputFile, \"standard input\")) {\r\n inputFileDiv.attr(\"style\", \"font-weight: bold\");\r\n }\r\n\r\n if (!endsWith(outputFile, \"standard output\")\r\n && !endsWith(outputFile, \"standard output\")) {\r\n outputFileDiv.attr(\"style\", \"font-weight: bold\");\r\n }\r\n\r\n const titleDiv = $(\"div.header div.title\");\r\n\r\n\r\n\r\n String.prototype.replaceAll = function (search, replace) {\r\n return this.split(search).join(replace);\r\n };\r\n\r\n $(\".sample-test 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clipboard\");\r\n }\r\n e.clearSelection();\r\n });\r\n });\r\n\r\n $(\".test-form-item input\").change(function () {\r\n addPendingSubmissionMessage($($(this).closest(\"form\")), \"You changed the answer, do not forget to submit it if you want to save the changes\");\r\n const index = $(this).closest(\".problemindexholder\").attr(\"problemindex\");\r\n let test = \"\";\r\n $(this).closest(\"form input\").each(function () {\r\n const test_ = $(this).attr(\"name\");\r\n if (test_ && test_.substring(0, 4) === \"test\") {\r\n test = test_;\r\n }\r\n });\r\n if (index.length > 0 && test.length > 0) {\r\n const indexTest = index + \"::\" + test;\r\n window.changedTests.add(indexTest);\r\n }\r\n });\r\n\r\n $(window).on('beforeunload', function () {\r\n if (window.changedTests.size > 0) {\r\n return 'Dialog text here';\r\n }\r\n });\r\n\r\n autosize($('.test-explanation textarea'));\r\n\r\n $(\".test-example-line\").hover(function() {\r\n $(this).attr(\"class\").split(\" \").forEach((clazz) 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, 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href=\"#\" class=\"topic-vote-up-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+9</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/786#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/786#comments\">\n 5\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div 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Testing"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">K. Testing</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>You take part in the testing of new weapon. For the testing a polygon was created. The polygon is a rectangular field <span class=\"tex-span\"><i>n</i> × <i>m</i></span> in size, divided into unit squares <span class=\"tex-span\">1 × 1</span> in size. The polygon contains <span class=\"tex-span\"><i>k</i></span> objects, each of which is a rectangle with sides, parallel to the polygon sides and entirely occupying several unit squares. The objects don't intersect and don't touch each other.</p><p>The principle according to which the weapon works is highly secret. You only know that one can use it to strike any rectangular area whose area is not equal to zero with sides, parallel to the sides of the polygon. The area must completely cover some of the unit squares into which the polygon is divided and it must not touch the other squares. Of course the area mustn't cross the polygon border. Your task is as follows: you should hit no less than one and no more than three rectangular objects. Each object must either lay completely inside the area (in that case it is considered to be hit), or lay completely outside the area.</p><p>Find the number of ways of hitting.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line has three integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> и <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 1000</span>, <span class=\"tex-span\">1 ≤ <i>k</i> ≤ 90</span>) — the sizes of the polygon and the number of objects on it respectively. Next <span class=\"tex-span\"><i>n</i></span> lines contain <span class=\"tex-span\"><i>m</i></span> symbols each and describe the polygon. The symbol \"<span class=\"tex-font-style-tt\">*</span>\" stands for a square occupied an object, whereas the symbol \"<span class=\"tex-font-style-tt\">.</span>\" stands for an empty space. The symbols \"<span class=\"tex-font-style-tt\">*</span>\" form exactly <span class=\"tex-span\"><i>k</i></span> rectangular connected areas that meet the requirements of the task.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a single number — the number of different ways to hit a target.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3 3<br/>*.*<br/>...<br/>*..<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>21<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 5 4<br/>.*.**<br/>...**<br/>**...<br/>...**<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>38<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 1<br/>.*<br/>..<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"1a3315146bceea273e2b88b5c0e02c85\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - K - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"c1de445efc0202970e7fe88a239610d2e54bf46e\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - K - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/39\">School Team Contest 1 (Winter Computer School 2010/11)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='1a3315146bceea273e2b88b5c0e02c85'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/39/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2600\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='1a3315146bceea273e2b88b5c0e02c85'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"184\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='1a3315146bceea273e2b88b5c0e02c85'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"184\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/781\" title=\"School Team Contest #1 (Winter Computer School 2010/11)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"541:542\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/786\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Tutorial\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"543:544\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/793\" title=\"School Team Contest #1 (Winter Computer School 2010/11): Problem K Tutorial\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"768:769\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/39\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/39/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/39/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/39/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/39/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/39/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem 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}\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"K\" data-uuid=\"ps_e8d3d9cd1e2e400100c2e04f4927152ea32e4765\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">K. Testing</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>64 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>You take part in the testing of new weapon. For the testing a polygon was created. The polygon is a rectangular field <span class=\"tex-span\"><i>n</i> × <i>m</i></span> in size, divided into unit squares <span class=\"tex-span\">1 × 1</span> in size. The polygon contains <span class=\"tex-span\"><i>k</i></span> objects, each of which is a rectangle with sides, parallel to the polygon sides and entirely occupying several unit squares. The objects don't intersect and don't touch each other.</p><p>The principle according to which the weapon works is highly secret. You only know that one can use it to strike any rectangular area whose area is not equal to zero with sides, parallel to the sides of the polygon. The area must completely cover some of the unit squares into which the polygon is divided and it must not touch the other squares. Of course the area mustn't cross the polygon border. Your task is as follows: you should hit no less than one and no more than three rectangular objects. Each object must either lay completely inside the area (in that case it is considered to be hit), or lay completely outside the area.</p><p>Find the number of ways of hitting.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line has three integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> и <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 1000</span>, <span class=\"tex-span\">1 ≤ <i>k</i> ≤ 90</span>) — the sizes of the polygon and the number of objects on it respectively. Next <span class=\"tex-span\"><i>n</i></span> lines contain <span class=\"tex-span\"><i>m</i></span> symbols each and describe the polygon. The symbol "<span class=\"tex-font-style-tt\">*</span>" stands for a square occupied an object, whereas the symbol "<span class=\"tex-font-style-tt\">.</span>" stands for an empty space. The symbols "<span class=\"tex-font-style-tt\">*</span>" form exactly <span class=\"tex-span\"><i>k</i></span> rectangular connected areas that meet the requirements of the task.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output a single number — the number of different ways to hit a target.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3 3<br />*.*<br />...<br />*..<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>21<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 5 4<br />.*.**<br />...**<br />**...<br />...**<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>38<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 1<br />.*<br />..<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='2c951d740f6f5fd942ba000fa1c74679'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/natalia\">natalia</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/natalia\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/natalia\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/natalia\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/natalia\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/natalia\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/natalia\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/natalia\" style=\"text-decoration:none;color:black !important;\">natalia's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"786\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/786\"> School Team Contest #1 (Winter Computer School 2010/11): Tutorial\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a>,\r\n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Problem A</b></div><div><br /></div><div>To get the maximal possible result you have just to sort summands in non-decreasing order by coefficients (counting coefficients with preceeding signs + and -). You should not pay attention to 'a++' or '++a'! The question is: why is it true? </div><div><br /></div><div>First, consider an expression with only 'a++'. Then our assertion is obvious: it is better to multiply 'a' by small coefficients when it has small value, and by large coefficients, when it becomes larger. The same also takes place in case of negative coefficients or a-value. Of course, it is not a rigorous proof. I hope you will think on it if you haven't get it yet.</div><div><br /></div><div>Second, consider the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>k</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> is some coefficient equal for both summands. Let initial value of 'a' equals to <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">0</sub></span>. Calculating the value of the expression both ways, we obtain: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2) = <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. So in this case the order is immaterial.</div><div><br /></div><div>Third, let us have the expression <span class=\"tex-span\"><i>k</i> * <i>a</i> + + + <i>l</i> * + + <i>a</i></span>, where <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>l</i></span> are two distinct coefficients. This expression can have two different values: <span class=\"tex-span\"><i>k</i> * <i>a</i><sub class=\"lower-index\">0</sub> + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 2)</span> and <span class=\"tex-span\"><i>k</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1) + <i>l</i> * (<i>a</i><sub class=\"lower-index\">0</sub> + 1)</span>. The first value is greater than the second one if and only if <span class=\"tex-span\"><i>k</i> < <i>l</i></span>. We can deal with the expression k*++a+l*a++ analogously.</div><div><br /></div><div>Thus if we have two succesive summands with the same coefficient, we may swap or not to swap them. If we have two succesive summands with distinct coefficients, we must put the summand with a smaller coeficient first. Applying these considerations while it is necessary, we get a sequence of summands sorted by coefficients. </div><div><br /></div><div> </div><div><b>Porblem B</b></div><div><br /></div><div>For this problem, the greedy solution is acceptable. Process given numbers consequently until <span class=\"tex-span\">1</span> is found. Then continue to process searching for <span class=\"tex-span\">2</span>, then for <span class=\"tex-span\">3</span>, etc.</div><div><br /></div><div><b>Problem C</b></div><div><br /></div><div>The authors solution takes <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> time and <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> memory. Solutions with <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/ca2e1829fa31a6050c856b85d6369a8d5172f35d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> time and <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span> memory are also acceptable.</div><div><br /></div><div>Let us reformulate the problem. Given a set of segments on a line, and the task is to find the largest subset such that segments in it don't intersect ``partially''. Two segments <span class=\"tex-span\">[<i>a</i>, <i>b</i>]</span> and <span class=\"tex-span\">[<i>c</i>, <i>d</i>]</span> intersect partially, if, for instance, <span class=\"tex-span\"><i>a</i> < <i>c</i> < <i>b</i> < <i>d</i></span>.</div><div><br /></div><div>Take all the ends of the given segments, sort them, and compute the dynamics: <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> is the largest possible size of such subset that segments in don't intersect partially and located between the <span class=\"tex-span\"><i>l</i></span>-th end and the <span class=\"tex-span\"><i>r</i></span> end (in sorted order), inclusively. We want to compute <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span> having already computed <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i>, <i>j</i></sub></span> for all <span class=\"tex-span\"><i>l</i> ≤ <i>i</i> ≤ <i>j</i> ≤ <i>r</i></span>, but <span class=\"tex-span\">[<i>i</i>, <i>j</i>] ≠ [<i>l</i>, <i>r</i>]</span>. First put <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub> = <i>d</i><sub class=\"lower-index\"><i>l</i> + 1, <i>r</i></sub></span> if we don't take segments with the left end in <span class=\"tex-span\"><i>l</i></span>. Now process the segments with the left end in <span class=\"tex-span\"><i>l</i></span>. If the segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> exists, we undoubtedly take it to our set. If we take another segment, say, <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span>, where <span class=\"tex-span\"><i>i</i> < <i>r</i></span>, look at segments <span class=\"tex-span\">[<i>l</i>, <i>i</i>]</span> and <span class=\"tex-span\">[<i>i</i>, <i>r</i>]</span> (we have answers for them already computed) and try to update <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>l</i>, <i>r</i></sub></span>. The asymptotics is <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>, because the total number of left ends is <span class=\"tex-span\"><i>O</i>(<i>n</i>)</span>. Then you have to output the certificate, i.e. the optimal set itself. It can be done in the standard way.</div><div><br /></div><div><b>Problem D</b></div><div><br /></div><div>The flies can NOT see each other iff they are in opposite vertices. You may use multiple ways to check this. For instance, you can check the Manhattan distance <span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\">1</sub> - <i>x</i><sub class=\"lower-index\">2</sub>| + |<i>y</i><sub class=\"lower-index\">1</sub> - <i>y</i><sub class=\"lower-index\">2</sub>| + |<i>z</i><sub class=\"lower-index\">1</sub> - <i>z</i><sub class=\"lower-index\">2</sub>| = 3</span> or the Euclidian distance <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/a93a95357d4680c51fb75f8121c744516bb7b82e.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. You can check if all three coorditanes are distinct (x1 != x2) && (y1 != y2) && (z1 != z2), or just (x1^x2)+(y1^y2)+(z1^z2) == 3!</div><div><br /></div><div><b>Problem E</b></div><div><br /></div><div>The number of ways to put <span class=\"tex-span\"><i>b</i></span> items into <span class=\"tex-span\"><i>a</i></span> boxes is, of course, <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup></span>. So we have an acyclic game for two players with positions <span class=\"tex-span\">(<i>a</i>, <i>b</i>)</span> for which <span class=\"tex-span\"><i>a</i><sup class=\"upper-index\"><i>b</i></sup> < <i>n</i></span>. Unfortunatly, there exists an infinite number of such positions: <span class=\"tex-span\"><i>a</i> = 1</span>, <span class=\"tex-span\"><i>b</i></span> is any. But in this case, if <span class=\"tex-span\">2<sup class=\"upper-index\"><i>b</i></sup> ≥ <i>n</i></span>, it is a draw position, because the only way for both players (not leading to lose) is to increase <span class=\"tex-span\"><i>b</i></span> infinitely. </div><div><br /></div><div>Another special case is a position with <span class=\"tex-span\"><i>b</i> = 1</span> and rather large <span class=\"tex-span\"><i>a</i></span>. Namely, if <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/eecd0fe013e9bca3f33792890991486c14d7b0b5.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, there is also only one move from this position - to increase <span class=\"tex-span\"><i>a</i></span>. If <span class=\"tex-span\"><i>a</i> = <i>n</i> - 1</span> the position is losing, if <span class=\"tex-span\"><i>a</i> = <i>n</i> - 2</span> it is winning, for <span class=\"tex-span\"><i>a</i> = <i>n</i> - 3</span> it is losing again and so on.</div><div><br /></div><div>Thus we have two kinds of positions to deal with them specially. The number of other positions is not very large, and you can compute the standard dynamics for acyclic games for them.</div><div><br /></div><div><b>Problem F</b></div><div><br /></div><div>The simple modelling of frog's jumps works too long, because <span class=\"tex-span\"><i>n</i></span> can be <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span>. The right solution is to count for each frog a number of smashed mosquitoes by checking divisibility of numbers of hills with mosquitoes by <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span>.</div><div><br /></div><div><b>Problem G</b></div><div><br /></div><div>What can I say about problem G? You should parse a given function and calculate its value for all values of <span class=\"tex-span\"><i>n</i></span>. Of course, it is impossible to do it just implementing the recursion, because this can work too long (see example with Fibonacci sequence). So you should use dynamic programming.</div><div><br /></div><div><b>Problem H</b></div><div><br /></div><div>You have to calculate all products <span class=\"tex-span\"><i>i</i> * <i>j</i></span>, and output them in the system of notations with radix <span class=\"tex-span\"><i>k</i></span>.</div><div><br /></div><div><b>Problem I</b></div><div><br /></div><div>Consider only the part of the graph reachable from <span class=\"tex-span\">1</span>. The task is to find the largest number <span class=\"tex-span\"><i>t</i></span>, such that a chosen set of vertices is reachable only at moments divisible by <span class=\"tex-span\"><i>t</i></span>. Suppose we have built such a set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span>. Look at sets <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">1</sub></span>, <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">2</sub></span>, ..., <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\"><i>t</i> - 1</sub></span> of all vertices reachable at moments having remainders <span class=\"tex-span\">1</span>, <span class=\"tex-span\">2</span>, ..., <span class=\"tex-span\"><i>t</i> - 1</span> modulo <span class=\"tex-span\"><i>t</i></span>, respectively. One can easily check that these sets are disjoint, and their union coinside with the set of all reacheble vertices. Clearly, that the edge from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span> can exist only when <span class=\"tex-span\"><i>u</i></span> and <span class=\"tex-span\"><i>v</i></span> belong to consequetive sets, i.e. <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/825126b16102dc3a249f4e4b341abcbd08cf0f8d.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7b1fab211e209ef06149fb06e532296d2d36bf38.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, <span class=\"tex-span\"><i>k</i> + 1</span> is taken modulo <span class=\"tex-span\"><i>t</i></span>.</div><div><br /></div><div>For each vertex <span class=\"tex-span\"><i>v</i></span>, find a distance <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>v</i></sub></span> from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>v</i></span> (if there is multiple paths, choose any, for example, by dfs). If the edge exists from <span class=\"tex-span\"><i>u</i></span> to <span class=\"tex-span\"><i>v</i></span>, it must be <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/3acaa745384ffbf31eba63169f52f2a061411cac.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. By analyzing all the edges, we come to the conclusion that the optimal value of <span class=\"tex-span\"><i>t</i></span> equals to the greatest common divisor of the numbers <span class=\"tex-span\">|<i>d</i><sub class=\"lower-index\"><i>u</i></sub> + 1 - <i>d</i><sub class=\"lower-index\"><i>v</i></sub>|</span>. To find the set <span class=\"tex-span\"><i>S</i><sub class=\"lower-index\">0</sub></span> is not very difficult now.</div><div><br /></div><div><b>Problem J</b></div><div><br /></div><div>The simplest solution is to find two numbers <span class=\"tex-span\"><i>l</i></span> and <span class=\"tex-span\"><i>r</i></span> - the length of the longest common prefix and the length of the longest common suffix of two strings, respectively. If <span class=\"tex-span\"><i>l</i> + 1 < <i>n</i> - <i>r</i></span> then there is no solution. Here <span class=\"tex-span\"><i>n</i></span> is the length of the first string. Otherwise we should output positions from <span class=\"tex-span\"><i>max</i>(<i>n</i> - <i>r</i>, 1)</span> to <span class=\"tex-span\"><i>min</i>(<i>l</i> + 1, <i>n</i>)</span>.</div><div><br /></div></div><div><div style=\"font-weight: bold;\">Problem K</div><div style=\"font-weight: bold;\"><br /></div><div>Problem K has a great number of different solutions, so I'm surprised that there was a lack of them during the contest. Solutions with time <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> and even some <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span> solutions with optimization were acceptable, but <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/KADR\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Lieutenant colonel KADR\">KADR</a> </span>describes even better solution in <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span> (<a href=\"https://codeforces.com/blog/entry/793\">http://codeforces.com/blog/entry/793</a>).</div></div><div><br /></div><div>Here are some jury ideas of this problem. First, let us compress the coordinates. Choose a labeled point in each object and compute by the standard dynamics the number of such labels in each rectangle. It takes <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">4</sup>)</span> to process all possible rectangles. The problem arises that a rectangle may contain a valid number of objects, but contain some objects not completely. To prevent this, we can check the borders. They are segments parallel to the coordinate axes, and their number is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">3</sup>)</span>. So we can precalc for them if they are valid or not comparing them with each object. Then we have to come back to uncompressed coordinates.</div><div><br /></div><div>The following solution is <span class=\"tex-span\"><i>O</i>(<i>k</i><sup class=\"upper-index\">5</sup>)</span>, and it uses the limitation on the number of objects (3) inside the rectangle. Process all the triples of objects (the same, of course, with pairs and single objects). Fix a triple, and change it by a single big object. Then move from the resulting object up (and then down), and check if a row above (or below) can be included in a striked rectangle. For each row we find a longest segment [l, r], which contains the current big object and doesn't contain others. Using this information, one can easily calculate the total number of rectangles that contain the current triple. </div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/39\" class=\"notice\" style=\"text-decoration: none;\">School Team Contest 1 (Winter Computer School 2010/11)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-2326-786\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"2326\",\n blogEntryId: \"786\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=school\" class=\"tag notice\" style=\"text-decoration: none;\">school</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=team\" class=\"tag notice\" style=\"text-decoration: none;\">team</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+9</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-786\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/natalia\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/natalia\">\n natalia\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Oct/24/2010 16:10\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/786#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/786#comments\">\n 5\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"796\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (5)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13100\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lijunle\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/lijunle\" title=\"Expert lijunle\" class=\"rated-user user-blue\">lijunle</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:08\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13100\" href=\"?#comment-13100\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13100\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3498\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13100\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span> <div class=\"from-renderer\">What is the test 12 of Problem A?<br /></div> </span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13100 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13100 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13100\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13101\" commentParentId=\"13100\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2010 20:27\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13101\" href=\"?#comment-13101\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13100\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13101\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13101\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Test 12 is a big random test</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13101 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13101 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13101\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13115\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 06:48\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13115\" href=\"?#comment-13115\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13115\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13115\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">So what is the test 8 of Problem C?</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13115 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13115 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13115\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13123\" commentParentId=\"13115\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/natalia\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1260/avatar/27f2d1c8595d0715.jpg'/> </a>\n <div><a href=\"/profile/natalia\" title=\"Master natalia\" class=\"rated-user user-orange\">natalia</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 11:09\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13123\" href=\"?#comment-13123\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13115\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13123\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1260\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13123\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><span style=\"border-collapse: collapse;font-family: arial , sans-serif;font-size: 13.0px;\"><pre style=\"margin-top: 0.0px;margin-right: 0.0px;margin-bottom: 0.0px;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-size: 12.0px;\">5\n2 1\n4 1\n6 1\n8 1\n5 3</pre></span></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13123 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13123 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13123\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"13145\" commentParentId=\"13123\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/zjf.sjtu\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/zjf.sjtu\" title=\"Expert zjf.sjtu\" class=\"rated-user user-blue\">zjf.sjtu</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/30/2010 19:07\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-13145\" href=\"?#comment-13145\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-13123\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"13145\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"7547\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-13145\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you,now I've got the wrong.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-13145 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-13145 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-13145\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div 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Find Color"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Find Color</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Not so long ago as a result of combat operations the main Berland place of interest — the magic clock — was damaged. The cannon's balls made several holes in the clock, that's why the residents are concerned about the repair. The magic clock can be represented as an <span class=\"tex-font-style-bf\">infinite</span> Cartesian plane, where the origin corresponds to the clock center. The clock was painted two colors as is shown in the picture:</p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/35f3d1d5170d481e2d4b0f4e0be1778f063c7eba.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/> </center><p>The picture shows only the central part of the clock. This coloring naturally extends to infinity.</p><p>The balls can be taken to be points on the plane. Your task is to find the color of the area, damaged by the given ball.</p><p>All the points located on the border of one of the areas have to be considered painted black.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first and single line contains two integers <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> — the coordinates of the hole made in the clock by the ball. Each of the numbers <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> has an absolute value that does not exceed <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Find the required color.</p><p>All the points between which and the origin of coordinates the distance is integral-value are painted black.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>-2 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>white<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>black<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>black<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"a2a5daf2daffc0c837becb5949a146d5\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"8f18df365110f9f39e201e49a37c61746b1357f8\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/40\">Codeforces Beta Round 39</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/40/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Constructive algorithms\">\r\n constructive algorithms\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Geometry, computational geometry\">\r\n geometry\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Mathematics including integration, differential equations, etc\">\r\n math\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1300\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='a2a5daf2daffc0c837becb5949a146d5'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"198\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" 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style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"160:161\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/835\" title=\"Codeforces Beta Round #39 (Разбор задач)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"553\" resourceName=\"Codeforces Beta Round #39 (Разбор задач)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/829\" title=\"codeforces #39\" target=\"_blank\">codeforces #39 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"162\" resourceName=\"codeforces #39\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/40\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/40/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/40/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/40/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/40/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/40/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/40/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/40/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n 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class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_49088c887316c2f45db8ad286a9f4ae2448f1b40\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Find Color</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Not so long ago as a result of combat operations the main Berland place of interest — the magic clock — was damaged. The cannon's balls made several holes in the clock, that's why the residents are concerned about the repair. The magic clock can be represented as an <span class=\"tex-font-style-bf\">infinite</span> Cartesian plane, where the origin corresponds to the clock center. The clock was painted two colors as is shown in the picture:</p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/35f3d1d5170d481e2d4b0f4e0be1778f063c7eba.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> </center><p>The picture shows only the central part of the clock. This coloring naturally extends to infinity.</p><p>The balls can be taken to be points on the plane. Your task is to find the color of the area, damaged by the given ball.</p><p>All the points located on the border of one of the areas have to be considered painted black.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first and single line contains two integers <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> — the coordinates of the hole made in the clock by the ball. Each of the numbers <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> has an absolute value that does not exceed <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Find the required color.</p><p>All the points between which and the origin of coordinates the distance is integral-value are painted black.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>-2 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>white<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>black<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>black<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=A]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if (result[\"success\"] === \"true\") {\r\n Codeforces.facebox(\".diff-popup\", \"//codeforces.org/s/73366\");\r\n 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='a2448587f0b0309e076af46c2a86694c'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/Seyaua\">Seyaua</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/Seyaua\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/Seyaua\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/Seyaua\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/Seyaua\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/Seyaua\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/Seyaua\" style=\"text-decoration:none;color:black !important;\">Seyaua's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"835\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/835\"> <p>Codeforces Beta Round #39 (Разбор задач)</p>\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/Seyaua\" title=\"Master Seyaua\" class=\"rated-user user-orange\">Seyaua</a>,\r\n <span class=\"format-humantime\" title=\"Nov/06/2010 23:53\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><b><div>Задача A. Определите цвет</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Здесь все понятно. Достаточно рассмотреть несколько случаев. Первый — когда расстояние от <b><div style=\"font-weight: normal;display: inline !important;\">точки до начала координат — целое число, тогда ответ black. В противном случае, пусть <span class=\"tex-span\"><i>d</i></span> </div></b><b><div style=\"font-weight: normal;display: inline !important;\">- это расстояние от нашей точки до начала координат. Тогда будем работать с <span class=\"tex-span\">[<i>d</i>]</span>. Теперь </div></b><b><div style=\"font-weight: normal;display: inline !important;\">осталось два случая: 1) если наша точка лежит в 1-ой, или 3-ей четверти; 2) точка лежит во </div></b><b><div style=\"font-weight: normal;display: inline !important;\">2-ой, либо 4-ой четверти. В случае 1) имеем, если <span class=\"tex-span\">[<i>d</i>]</span> нечетно, то ответ white, иначе </div></b><b><div style=\"font-weight: normal;display: inline !important;\">black; в случае 2) если <span class=\"tex-span\">[<i>d</i>]</span> четно, то ответ white, иначе black. Подразумевается, что </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\">[<i>d</i>]</span> — целая часть <span class=\"tex-span\"><i>d</i></span>.</div></b></div><div style=\"font-weight: normal;\"><br /></div><div>Задача B. Перекрашивания</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Первое, что надо заметить, так это то, что на i-ом шаге все перекрашенные клетки будут <b><div style=\"font-weight: normal;display: inline !important;\">лежать в прямоугольнике с вершинами в клетках (i,i), (n-i,m-i) (если считать, что (1,1) - </div></b><b><div style=\"font-weight: normal;display: inline !important;\">левая верхняя клетка, а (n,m) — правая нижняя). Тогда отсюда уже следует решение: нужно </div></b><b><div style=\"font-weight: normal;display: inline !important;\">подсчитать количество клеток такого типа, что минимальное расстояние до стороны в точности </div></b><b><div style=\"font-weight: normal;display: inline !important;\">равняется x. То есть для клетки (a,b) должно выполняться </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\"><i>min</i>(<i>min</i>(<i>a</i>, <i>b</i>), <i>min</i>(<i>n</i> - <i>a</i> + 1, <i>m</i> - <i>b</i> + 1)) = <i>x</i></span>.</div></b></div></b></div><div><b><br /></b></div><div><b>Задача C. Берляндская площадь</b></div><div><br /></div><div>Идейно эта задача не очень сложная, но было много хитрых случаев. Авторское решение предполагало следующую идею. Сначала заметим, что наше множество окружностей на плоскости может быть несвязным. Тут есть два случая, когда есть хотя бы одна точка пересечения окружностей и когда нет ни одной. Если их нет, то ответ N+M+1. Иначе, если есть хотя бы одна точка пересечения, то мы можем удалить некоторые окружности таким образом, чтобы оставшаяся фигура из окружностей была связной. Тогда для этой фигуры можно применить <a href=\"https://ru.wikipedia.org/wiki/Планарный_граф\">формулу Эйлера</a>. Таким образом, нам здесь нужно посчитать количество точек пересечения и количество дуг-ребер. Нетрудно видеть, что каждая точка пересечения добавляет две дуги. Таким образом, мы можем найти количество частей, на которые разделилась плоскость без удаленных окружностей. Теперь достаточно заметить, что каждая удаленная окружность добавляет ровно 1 к ответу. Весь вопрос в том, чтобы посчитать, сколько точек пересечения. Это можно сделать за O(N+M), если считать для каждой окружности, точки пересечения, которые принадлежат ей. Для этого достаточно заметить, что все окружности, с которыми наша окружность пересекается будут иметь радиусы l, l+1, ..., r. Также, с некоторыми из этих окружностей наша окружность будет иметь не две точки пересечения а одну. Это необходимо учесть в решении. После этого остается лишь аккуратно реализовать эту идею. </div><div><br /></div><div><b>Задача D. Интересная последовательность</b></div><div><br /></div><div>Здесь нужно было погенерировать разные последовательности, которые могут получаться и внимательно смотреть на полученные значения. Основное наблюдение, это то, что каждое из чисел, которые встречаются в последовательности имеет вид <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, при этом это число может встречаться лишь на позиции <span class=\"tex-span\">(<i>k</i> + <i>m</i> + 1)</span>. Теперь, когда известен общий вид, можно по методу математической индукции доказать, что на <span class=\"tex-span\"><i>x</i></span>-ой позиции могут встречаться все числа вида <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, такие что, <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span>. После этого можно было реализовать простое в написании решение за <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">3</sup>)</span>, где <span class=\"tex-span\"><i>N</i></span> — длина входного числа. Для этого перебираем все x от 1 до 600 и проверяем, существуют ли такие <span class=\"tex-span\"><i>k</i></span> и <span class=\"tex-span\"><i>m</i></span>, что <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span> и <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup> = <i>A</i></span>. Но также есть и решение со сложностью <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">2</sup>)</span>.</div><div><br /></div><div><b>Задача E. Таблица из чисел</b></div><div><br /></div><div>Первое, что должно было броситься в глаза, это то, что клеток, изначально не пустых — совсем мало. Из ограничений следует, что всегда есть пустая строка либо пустой столбец. Без ограничений общности можем считать, что у нас есть пустая строка и она последняя. Тогда выберем какой-либо столбец (к примеру, последний) и зафиксируем его одновременно с пустой строкой. Тогда по оставшейся таблице размера <span class=\"tex-span\">(<i>n</i> - 1) × (<i>m</i> - 1)</span> клетки в последнем столбце и в последней строке заполняются однозначно. Но есть одно замечание, в последнем столбце уже стоят какие-то числа. Тогда нам надо для каждой строки, кроме последней подсчитать, сколько существует вариантов этой строки, таких, что произведение чисел в этой строке равно -1. В авторском решении, эта часть считалась при помощи динамического программирования. После этого нужно перемножить полученные ответы для каждой строки. Тогда ответ на задачу — это полученное произведение, либо 0 — если сумма <span class=\"tex-span\"><i>n</i> + <i>m</i></span> нечетна.</div><div><br /></div> <div></div><div><br /></div>Разбор задач был подготовлен мной и <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/sdya\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Colonel sdya\">sdya</a></span>. </div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-140-835\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"140\",\n blogEntryId: \"835\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2339\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #39</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80\" class=\"tag notice\" style=\"text-decoration: none;\">разбор</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" 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href=\"/profile/Seyaua\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/Seyaua\">\n Seyaua\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Nov/06/2010 23:53\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/835#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/835#comments\">\n 1\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments 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Repaintings"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Repaintings</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>A chessboard <span class=\"tex-span\"><i>n</i> × <i>m</i></span> in size is given. During the zero minute we repaint all the black squares to the 0 color. During the <span class=\"tex-span\"><i>i</i></span>-th minute we repaint to the <span class=\"tex-span\"><i>i</i></span> color the <span class=\"tex-font-style-bf\">initially black</span> squares that have exactly four corner-adjacent squares painted <span class=\"tex-span\"><i>i</i> - 1</span> (all such squares are repainted simultaneously). This process continues ad infinitum. You have to figure out how many squares we repainted exactly <span class=\"tex-span\"><i>x</i></span> times.</p><p>The upper left square of the board has to be assumed to be always black. Two squares are called corner-adjacent, if they have exactly one common point.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 5000</span>). The second line contains integer <span class=\"tex-span\"><i>x</i></span> (<span class=\"tex-span\">1 ≤ <i>x</i> ≤ 10<sup class=\"upper-index\">9</sup></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print how many squares will be painted exactly <span class=\"tex-span\"><i>x</i></span> times.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br/>1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br/>2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 1<br/>1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"53535a85bcce59fa60c7badbfdf07874\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"8f18df365110f9f39e201e49a37c61746b1357f8\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/40\">Codeforces Beta Round 39</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='53535a85bcce59fa60c7badbfdf07874'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/40/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Mathematics including integration, differential equations, etc\">\r\n math\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1600\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='53535a85bcce59fa60c7badbfdf07874'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"199\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='53535a85bcce59fa60c7badbfdf07874'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"199\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/820\" title=\"Codeforces Beta Round #39\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"160:161\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/835\" title=\"Codeforces Beta Round #39 (Разбор задач)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"553\" resourceName=\"Codeforces Beta Round #39 (Разбор задач)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/829\" title=\"codeforces #39\" target=\"_blank\">codeforces #39 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"162\" resourceName=\"codeforces #39\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/40\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/40/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/40/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/40/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/40/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/40/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/40/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/40/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation 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result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"B\" data-uuid=\"ps_e196646dcb1997fa0428ad1f27bc6a2dcf5ef0c4\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Repaintings</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>A chessboard <span class=\"tex-span\"><i>n</i> × <i>m</i></span> in size is given. During the zero minute we repaint all the black squares to the 0 color. During the <span class=\"tex-span\"><i>i</i></span>-th minute we repaint to the <span class=\"tex-span\"><i>i</i></span> color the <span class=\"tex-font-style-bf\">initially black</span> squares that have exactly four corner-adjacent squares painted <span class=\"tex-span\"><i>i</i> - 1</span> (all such squares are repainted simultaneously). This process continues ad infinitum. You have to figure out how many squares we repainted exactly <span class=\"tex-span\"><i>x</i></span> times.</p><p>The upper left square of the board has to be assumed to be always black. Two squares are called corner-adjacent, if they have exactly one common point.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 5000</span>). The second line contains integer <span class=\"tex-span\"><i>x</i></span> (<span class=\"tex-span\">1 ≤ <i>x</i> ≤ 10<sup class=\"upper-index\">9</sup></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print how many squares will be painted exactly <span class=\"tex-span\"><i>x</i></span> times.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br />1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br />2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 1<br />1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='a2448587f0b0309e076af46c2a86694c'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/Seyaua\">Seyaua</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/Seyaua\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/Seyaua\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/Seyaua\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/Seyaua\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/Seyaua\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/Seyaua\" style=\"text-decoration:none;color:black !important;\">Seyaua's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"835\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/835\"> <p>Codeforces Beta Round #39 (Разбор задач)</p>\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/Seyaua\" title=\"Master Seyaua\" class=\"rated-user user-orange\">Seyaua</a>,\r\n <span class=\"format-humantime\" title=\"Nov/06/2010 23:53\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><b><div>Задача A. Определите цвет</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Здесь все понятно. Достаточно рассмотреть несколько случаев. Первый — когда расстояние от <b><div style=\"font-weight: normal;display: inline !important;\">точки до начала координат — целое число, тогда ответ black. В противном случае, пусть <span class=\"tex-span\"><i>d</i></span> </div></b><b><div style=\"font-weight: normal;display: inline !important;\">- это расстояние от нашей точки до начала координат. Тогда будем работать с <span class=\"tex-span\">[<i>d</i>]</span>. Теперь </div></b><b><div style=\"font-weight: normal;display: inline !important;\">осталось два случая: 1) если наша точка лежит в 1-ой, или 3-ей четверти; 2) точка лежит во </div></b><b><div style=\"font-weight: normal;display: inline !important;\">2-ой, либо 4-ой четверти. В случае 1) имеем, если <span class=\"tex-span\">[<i>d</i>]</span> нечетно, то ответ white, иначе </div></b><b><div style=\"font-weight: normal;display: inline !important;\">black; в случае 2) если <span class=\"tex-span\">[<i>d</i>]</span> четно, то ответ white, иначе black. Подразумевается, что </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\">[<i>d</i>]</span> — целая часть <span class=\"tex-span\"><i>d</i></span>.</div></b></div><div style=\"font-weight: normal;\"><br /></div><div>Задача B. Перекрашивания</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Первое, что надо заметить, так это то, что на i-ом шаге все перекрашенные клетки будут <b><div style=\"font-weight: normal;display: inline !important;\">лежать в прямоугольнике с вершинами в клетках (i,i), (n-i,m-i) (если считать, что (1,1) - </div></b><b><div style=\"font-weight: normal;display: inline !important;\">левая верхняя клетка, а (n,m) — правая нижняя). Тогда отсюда уже следует решение: нужно </div></b><b><div style=\"font-weight: normal;display: inline !important;\">подсчитать количество клеток такого типа, что минимальное расстояние до стороны в точности </div></b><b><div style=\"font-weight: normal;display: inline !important;\">равняется x. То есть для клетки (a,b) должно выполняться </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\"><i>min</i>(<i>min</i>(<i>a</i>, <i>b</i>), <i>min</i>(<i>n</i> - <i>a</i> + 1, <i>m</i> - <i>b</i> + 1)) = <i>x</i></span>.</div></b></div></b></div><div><b><br /></b></div><div><b>Задача C. Берляндская площадь</b></div><div><br /></div><div>Идейно эта задача не очень сложная, но было много хитрых случаев. Авторское решение предполагало следующую идею. Сначала заметим, что наше множество окружностей на плоскости может быть несвязным. Тут есть два случая, когда есть хотя бы одна точка пересечения окружностей и когда нет ни одной. Если их нет, то ответ N+M+1. Иначе, если есть хотя бы одна точка пересечения, то мы можем удалить некоторые окружности таким образом, чтобы оставшаяся фигура из окружностей была связной. Тогда для этой фигуры можно применить <a href=\"https://ru.wikipedia.org/wiki/Планарный_граф\">формулу Эйлера</a>. Таким образом, нам здесь нужно посчитать количество точек пересечения и количество дуг-ребер. Нетрудно видеть, что каждая точка пересечения добавляет две дуги. Таким образом, мы можем найти количество частей, на которые разделилась плоскость без удаленных окружностей. Теперь достаточно заметить, что каждая удаленная окружность добавляет ровно 1 к ответу. Весь вопрос в том, чтобы посчитать, сколько точек пересечения. Это можно сделать за O(N+M), если считать для каждой окружности, точки пересечения, которые принадлежат ей. Для этого достаточно заметить, что все окружности, с которыми наша окружность пересекается будут иметь радиусы l, l+1, ..., r. Также, с некоторыми из этих окружностей наша окружность будет иметь не две точки пересечения а одну. Это необходимо учесть в решении. После этого остается лишь аккуратно реализовать эту идею. </div><div><br /></div><div><b>Задача D. Интересная последовательность</b></div><div><br /></div><div>Здесь нужно было погенерировать разные последовательности, которые могут получаться и внимательно смотреть на полученные значения. Основное наблюдение, это то, что каждое из чисел, которые встречаются в последовательности имеет вид <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, при этом это число может встречаться лишь на позиции <span class=\"tex-span\">(<i>k</i> + <i>m</i> + 1)</span>. Теперь, когда известен общий вид, можно по методу математической индукции доказать, что на <span class=\"tex-span\"><i>x</i></span>-ой позиции могут встречаться все числа вида <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, такие что, <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span>. После этого можно было реализовать простое в написании решение за <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">3</sup>)</span>, где <span class=\"tex-span\"><i>N</i></span> — длина входного числа. Для этого перебираем все x от 1 до 600 и проверяем, существуют ли такие <span class=\"tex-span\"><i>k</i></span> и <span class=\"tex-span\"><i>m</i></span>, что <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span> и <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup> = <i>A</i></span>. Но также есть и решение со сложностью <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">2</sup>)</span>.</div><div><br /></div><div><b>Задача E. Таблица из чисел</b></div><div><br /></div><div>Первое, что должно было броситься в глаза, это то, что клеток, изначально не пустых — совсем мало. Из ограничений следует, что всегда есть пустая строка либо пустой столбец. Без ограничений общности можем считать, что у нас есть пустая строка и она последняя. Тогда выберем какой-либо столбец (к примеру, последний) и зафиксируем его одновременно с пустой строкой. Тогда по оставшейся таблице размера <span class=\"tex-span\">(<i>n</i> - 1) × (<i>m</i> - 1)</span> клетки в последнем столбце и в последней строке заполняются однозначно. Но есть одно замечание, в последнем столбце уже стоят какие-то числа. Тогда нам надо для каждой строки, кроме последней подсчитать, сколько существует вариантов этой строки, таких, что произведение чисел в этой строке равно -1. В авторском решении, эта часть считалась при помощи динамического программирования. После этого нужно перемножить полученные ответы для каждой строки. Тогда ответ на задачу — это полученное произведение, либо 0 — если сумма <span class=\"tex-span\"><i>n</i> + <i>m</i></span> нечетна.</div><div><br /></div> <div></div><div><br /></div>Разбор задач был подготовлен мной и <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/sdya\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Colonel sdya\">sdya</a></span>. </div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-140-835\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"140\",\n blogEntryId: \"835\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2339\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #39</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80\" class=\"tag notice\" style=\"text-decoration: none;\">разбор</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" 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href=\"/profile/Seyaua\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/Seyaua\">\n Seyaua\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Nov/06/2010 23:53\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/835#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/835#comments\">\n 1\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments 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Berland Square"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Berland Square</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Last year the world's largest square was built in Berland. It is known that the square can be represented as an infinite plane with an introduced Cartesian system of coordinates. On that square two sets of concentric circles were painted. Let's call the set of concentric circles with radii <span class=\"tex-span\">1, 2, ..., <i>K</i></span> and the center in the point <span class=\"tex-span\">(<i>z</i>, 0)</span> a <span class=\"tex-span\">(<i>K</i>, <i>z</i>)</span>-set. Thus, on the square were painted a <span class=\"tex-span\">(<i>N</i>, <i>x</i>)</span>-set and a <span class=\"tex-span\">(<i>M</i>, <i>y</i>)</span>-set. You have to find out how many parts those sets divided the square into.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>N</i>, <i>x</i>, <i>M</i>, <i>y</i></span>. (<span class=\"tex-span\">1 ≤ <i>N</i>, <i>M</i> ≤ 100000, - 100000 ≤ <i>x</i>, <i>y</i> ≤ 100000, <i>x</i> ≠ <i>y</i></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the sought number of parts.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1 0 1 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 0 1 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3 4 7<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>17<br/></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>Picture for the third sample:</p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/2c978915a69e3e144fae3543912b0912e461d77a.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/> </center></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"adafaf99166e5bf90305477dcb92d3dc\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"8f18df365110f9f39e201e49a37c61746b1357f8\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/40\">Codeforces Beta Round 39</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='adafaf99166e5bf90305477dcb92d3dc'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/40/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Mathematics including integration, differential equations, etc\">\r\n math\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2300\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='adafaf99166e5bf90305477dcb92d3dc'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"200\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='adafaf99166e5bf90305477dcb92d3dc'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"200\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm 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Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/820\" title=\"Codeforces Beta Round #39\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"160:161\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/835\" title=\"Codeforces Beta Round #39 (Разбор задач)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"553\" resourceName=\"Codeforces Beta Round #39 (Разбор задач)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/829\" title=\"codeforces #39\" target=\"_blank\">codeforces #39 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"162\" resourceName=\"codeforces #39\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul 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class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Berland Square</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Last year the world's largest square was built in Berland. It is known that the square can be represented as an infinite plane with an introduced Cartesian system of coordinates. On that square two sets of concentric circles were painted. Let's call the set of concentric circles with radii <span class=\"tex-span\">1, 2, ..., <i>K</i></span> and the center in the point <span class=\"tex-span\">(<i>z</i>, 0)</span> a <span class=\"tex-span\">(<i>K</i>, <i>z</i>)</span>-set. Thus, on the square were painted a <span class=\"tex-span\">(<i>N</i>, <i>x</i>)</span>-set and a <span class=\"tex-span\">(<i>M</i>, <i>y</i>)</span>-set. You have to find out how many parts those sets divided the square into.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>N</i>, <i>x</i>, <i>M</i>, <i>y</i></span>. (<span class=\"tex-span\">1 ≤ <i>N</i>, <i>M</i> ≤ 100000, - 100000 ≤ <i>x</i>, <i>y</i> ≤ 100000, <i>x</i> ≠ <i>y</i></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the sought number of parts.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1 0 1 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 0 1 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3 4 7<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>17<br /></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>Picture for the third sample:</p><center> <img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/2c978915a69e3e144fae3543912b0912e461d77a.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> </center></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='a2448587f0b0309e076af46c2a86694c'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/Seyaua\">Seyaua</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/Seyaua\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/Seyaua\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/Seyaua\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/Seyaua\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/Seyaua\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/Seyaua\" style=\"text-decoration:none;color:black !important;\">Seyaua's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"835\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/835\"> <p>Codeforces Beta Round #39 (Разбор задач)</p>\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/Seyaua\" title=\"Master Seyaua\" class=\"rated-user user-orange\">Seyaua</a>,\r\n <span class=\"format-humantime\" title=\"Nov/06/2010 23:53\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><b><div>Задача A. Определите цвет</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Здесь все понятно. Достаточно рассмотреть несколько случаев. Первый — когда расстояние от <b><div style=\"font-weight: normal;display: inline !important;\">точки до начала координат — целое число, тогда ответ black. В противном случае, пусть <span class=\"tex-span\"><i>d</i></span> </div></b><b><div style=\"font-weight: normal;display: inline !important;\">- это расстояние от нашей точки до начала координат. Тогда будем работать с <span class=\"tex-span\">[<i>d</i>]</span>. Теперь </div></b><b><div style=\"font-weight: normal;display: inline !important;\">осталось два случая: 1) если наша точка лежит в 1-ой, или 3-ей четверти; 2) точка лежит во </div></b><b><div style=\"font-weight: normal;display: inline !important;\">2-ой, либо 4-ой четверти. В случае 1) имеем, если <span class=\"tex-span\">[<i>d</i>]</span> нечетно, то ответ white, иначе </div></b><b><div style=\"font-weight: normal;display: inline !important;\">black; в случае 2) если <span class=\"tex-span\">[<i>d</i>]</span> четно, то ответ white, иначе black. Подразумевается, что </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\">[<i>d</i>]</span> — целая часть <span class=\"tex-span\"><i>d</i></span>.</div></b></div><div style=\"font-weight: normal;\"><br /></div><div>Задача B. Перекрашивания</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Первое, что надо заметить, так это то, что на i-ом шаге все перекрашенные клетки будут <b><div style=\"font-weight: normal;display: inline !important;\">лежать в прямоугольнике с вершинами в клетках (i,i), (n-i,m-i) (если считать, что (1,1) - </div></b><b><div style=\"font-weight: normal;display: inline !important;\">левая верхняя клетка, а (n,m) — правая нижняя). Тогда отсюда уже следует решение: нужно </div></b><b><div style=\"font-weight: normal;display: inline !important;\">подсчитать количество клеток такого типа, что минимальное расстояние до стороны в точности </div></b><b><div style=\"font-weight: normal;display: inline !important;\">равняется x. То есть для клетки (a,b) должно выполняться </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\"><i>min</i>(<i>min</i>(<i>a</i>, <i>b</i>), <i>min</i>(<i>n</i> - <i>a</i> + 1, <i>m</i> - <i>b</i> + 1)) = <i>x</i></span>.</div></b></div></b></div><div><b><br /></b></div><div><b>Задача C. Берляндская площадь</b></div><div><br /></div><div>Идейно эта задача не очень сложная, но было много хитрых случаев. Авторское решение предполагало следующую идею. Сначала заметим, что наше множество окружностей на плоскости может быть несвязным. Тут есть два случая, когда есть хотя бы одна точка пересечения окружностей и когда нет ни одной. Если их нет, то ответ N+M+1. Иначе, если есть хотя бы одна точка пересечения, то мы можем удалить некоторые окружности таким образом, чтобы оставшаяся фигура из окружностей была связной. Тогда для этой фигуры можно применить <a href=\"https://ru.wikipedia.org/wiki/Планарный_граф\">формулу Эйлера</a>. Таким образом, нам здесь нужно посчитать количество точек пересечения и количество дуг-ребер. Нетрудно видеть, что каждая точка пересечения добавляет две дуги. Таким образом, мы можем найти количество частей, на которые разделилась плоскость без удаленных окружностей. Теперь достаточно заметить, что каждая удаленная окружность добавляет ровно 1 к ответу. Весь вопрос в том, чтобы посчитать, сколько точек пересечения. Это можно сделать за O(N+M), если считать для каждой окружности, точки пересечения, которые принадлежат ей. Для этого достаточно заметить, что все окружности, с которыми наша окружность пересекается будут иметь радиусы l, l+1, ..., r. Также, с некоторыми из этих окружностей наша окружность будет иметь не две точки пересечения а одну. Это необходимо учесть в решении. После этого остается лишь аккуратно реализовать эту идею. </div><div><br /></div><div><b>Задача D. Интересная последовательность</b></div><div><br /></div><div>Здесь нужно было погенерировать разные последовательности, которые могут получаться и внимательно смотреть на полученные значения. Основное наблюдение, это то, что каждое из чисел, которые встречаются в последовательности имеет вид <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, при этом это число может встречаться лишь на позиции <span class=\"tex-span\">(<i>k</i> + <i>m</i> + 1)</span>. Теперь, когда известен общий вид, можно по методу математической индукции доказать, что на <span class=\"tex-span\"><i>x</i></span>-ой позиции могут встречаться все числа вида <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, такие что, <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span>. После этого можно было реализовать простое в написании решение за <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">3</sup>)</span>, где <span class=\"tex-span\"><i>N</i></span> — длина входного числа. Для этого перебираем все x от 1 до 600 и проверяем, существуют ли такие <span class=\"tex-span\"><i>k</i></span> и <span class=\"tex-span\"><i>m</i></span>, что <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span> и <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup> = <i>A</i></span>. Но также есть и решение со сложностью <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">2</sup>)</span>.</div><div><br /></div><div><b>Задача E. Таблица из чисел</b></div><div><br /></div><div>Первое, что должно было броситься в глаза, это то, что клеток, изначально не пустых — совсем мало. Из ограничений следует, что всегда есть пустая строка либо пустой столбец. Без ограничений общности можем считать, что у нас есть пустая строка и она последняя. Тогда выберем какой-либо столбец (к примеру, последний) и зафиксируем его одновременно с пустой строкой. Тогда по оставшейся таблице размера <span class=\"tex-span\">(<i>n</i> - 1) × (<i>m</i> - 1)</span> клетки в последнем столбце и в последней строке заполняются однозначно. Но есть одно замечание, в последнем столбце уже стоят какие-то числа. Тогда нам надо для каждой строки, кроме последней подсчитать, сколько существует вариантов этой строки, таких, что произведение чисел в этой строке равно -1. В авторском решении, эта часть считалась при помощи динамического программирования. После этого нужно перемножить полученные ответы для каждой строки. Тогда ответ на задачу — это полученное произведение, либо 0 — если сумма <span class=\"tex-span\"><i>n</i> + <i>m</i></span> нечетна.</div><div><br /></div> <div></div><div><br /></div>Разбор задач был подготовлен мной и <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/sdya\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Colonel sdya\">sdya</a></span>. </div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-140-835\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"140\",\n blogEntryId: \"835\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=beta+round+%2339\" class=\"tag notice\" style=\"text-decoration: none;\">beta round #39</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80\" class=\"tag notice\" style=\"text-decoration: none;\">разбор</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" 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href=\"/profile/Seyaua\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/Seyaua\">\n Seyaua\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Nov/06/2010 23:53\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/835#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/835#comments\">\n 1\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments 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Interesting Sequence"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Interesting Sequence</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>3 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Berland scientists noticed long ago that the world around them depends on Berland population. Due to persistent research in this area the scientists managed to find out that the Berland chronology starts from the moment when the first two people came to that land (it is considered to have happened in the first year). After one Berland year after the start of the chronology the population had already equaled 13 people (the second year). However, tracing the population number during the following years was an ultimately difficult task, still it was found out that if <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span> — the number of people in Berland in the year of <span class=\"tex-span\"><i>i</i></span>, then either <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub> = 12<i>d</i><sub class=\"lower-index\"><i>i</i> - 2</sub></span>, or <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub> = 13<i>d</i><sub class=\"lower-index\"><i>i</i> - 1</sub> - 12<i>d</i><sub class=\"lower-index\"><i>i</i> - 2</sub></span>. Of course no one knows how many people are living in Berland at the moment, but now we can tell if there could possibly be a year in which the country population equaled <span class=\"tex-span\"><i>A</i></span>. That's what we ask you to determine. Also, if possible, you have to find out in which years it could be (from the beginning of Berland chronology). Let's suppose that it could be in the years of <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>k</i></sub></span>. Then you have to define how many residents could be in the country during those years apart from the <span class=\"tex-span\"><i>A</i></span> variant. Look at the examples for further explanation.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integer <span class=\"tex-span\"><i>A</i></span> (<span class=\"tex-span\">1 ≤ <i>A</i> < 10<sup class=\"upper-index\">300</sup></span>). It is guaranteed that the number doesn't contain leading zeros.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>On the first output line print <span class=\"tex-font-style-tt\">YES</span>, if there could be a year in which the total population of the country equaled <span class=\"tex-span\"><i>A</i></span>, otherwise print <span class=\"tex-font-style-tt\">NO</span>. </p><p>If the answer is <span class=\"tex-font-style-tt\">YES</span>, then you also have to print number <span class=\"tex-span\"><i>k</i></span> — the number of years in which the population could equal <span class=\"tex-span\"><i>A</i></span>. On the next line you have to output precisely <span class=\"tex-span\"><i>k</i></span> space-separated numbers — <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>k</i></sub></span>. Those numbers have to be output in the increasing order.</p><p>On the next line you should output number <span class=\"tex-span\"><i>p</i></span> — how many variants of the number of people could be in the years of <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>k</i></sub></span>, apart from the <span class=\"tex-span\"><i>A</i></span> variant. On each of the next <span class=\"tex-span\"><i>p</i></span> lines you have to print one number — the sought number of residents. Those number also have to go in the increasing order. </p><p>If any number (or both of them) <span class=\"tex-span\"><i>k</i></span> or <span class=\"tex-span\"><i>p</i></span> exceeds <span class=\"tex-span\">1000</span>, then you have to print <span class=\"tex-span\">1000</span> instead of it and only the first <span class=\"tex-span\">1000</span> possible answers in the increasing order.</p><p>The numbers should have no leading zeros.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/>1<br/>1<br/>0<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>13<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/>1<br/>2<br/>0<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1729<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/>1<br/>4<br/>1<br/>156<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"ca67327cb5dd573c3362e78738f99905\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"8f18df365110f9f39e201e49a37c61746b1357f8\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/40\">Codeforces Beta Round 39</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='ca67327cb5dd573c3362e78738f99905'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/40/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Mathematics including integration, differential equations, etc\">\r\n math\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2600\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='ca67327cb5dd573c3362e78738f99905'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"201\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='ca67327cb5dd573c3362e78738f99905'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"201\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = 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class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/820\" title=\"Codeforces Beta Round #39\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"160:161\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/835\" title=\"Codeforces Beta Round #39 (Разбор задач)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"553\" resourceName=\"Codeforces Beta Round #39 (Разбор задач)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/829\" title=\"codeforces #39\" target=\"_blank\">codeforces #39 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"162\" resourceName=\"codeforces #39\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/40\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/40/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/40/my\">My Submissions</a></li>\r\n <li><a\r\n 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textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName 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result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_1ee3617cf8fe0b5f650f46750a5f9e89e446876b\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Interesting Sequence</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>3 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Berland scientists noticed long ago that the world around them depends on Berland population. Due to persistent research in this area the scientists managed to find out that the Berland chronology starts from the moment when the first two people came to that land (it is considered to have happened in the first year). After one Berland year after the start of the chronology the population had already equaled 13 people (the second year). However, tracing the population number during the following years was an ultimately difficult task, still it was found out that if <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub></span> — the number of people in Berland in the year of <span class=\"tex-span\"><i>i</i></span>, then either <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub> = 12<i>d</i><sub class=\"lower-index\"><i>i</i> - 2</sub></span>, or <span class=\"tex-span\"><i>d</i><sub class=\"lower-index\"><i>i</i></sub> = 13<i>d</i><sub class=\"lower-index\"><i>i</i> - 1</sub> - 12<i>d</i><sub class=\"lower-index\"><i>i</i> - 2</sub></span>. Of course no one knows how many people are living in Berland at the moment, but now we can tell if there could possibly be a year in which the country population equaled <span class=\"tex-span\"><i>A</i></span>. That's what we ask you to determine. Also, if possible, you have to find out in which years it could be (from the beginning of Berland chronology). Let's suppose that it could be in the years of <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>k</i></sub></span>. Then you have to define how many residents could be in the country during those years apart from the <span class=\"tex-span\"><i>A</i></span> variant. Look at the examples for further explanation.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integer <span class=\"tex-span\"><i>A</i></span> (<span class=\"tex-span\">1 ≤ <i>A</i> < 10<sup class=\"upper-index\">300</sup></span>). It is guaranteed that the number doesn't contain leading zeros.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>On the first output line print <span class=\"tex-font-style-tt\">YES</span>, if there could be a year in which the total population of the country equaled <span class=\"tex-span\"><i>A</i></span>, otherwise print <span class=\"tex-font-style-tt\">NO</span>. </p><p>If the answer is <span class=\"tex-font-style-tt\">YES</span>, then you also have to print number <span class=\"tex-span\"><i>k</i></span> — the number of years in which the population could equal <span class=\"tex-span\"><i>A</i></span>. On the next line you have to output precisely <span class=\"tex-span\"><i>k</i></span> space-separated numbers — <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>k</i></sub></span>. Those numbers have to be output in the increasing order.</p><p>On the next line you should output number <span class=\"tex-span\"><i>p</i></span> — how many variants of the number of people could be in the years of <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>k</i></sub></span>, apart from the <span class=\"tex-span\"><i>A</i></span> variant. On each of the next <span class=\"tex-span\"><i>p</i></span> lines you have to print one number — the sought number of residents. Those number also have to go in the increasing order. </p><p>If any number (or both of them) <span class=\"tex-span\"><i>k</i></span> or <span class=\"tex-span\"><i>p</i></span> exceeds <span class=\"tex-span\">1000</span>, then you have to print <span class=\"tex-span\">1000</span> instead of it and only the first <span class=\"tex-span\">1000</span> possible answers in the increasing order.</p><p>The numbers should have no leading zeros.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br />1<br />1<br />0<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>13<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br />1<br />2<br />0<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1729<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br />1<br />4<br />1<br />156<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='a2448587f0b0309e076af46c2a86694c'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n </label>\r\n </div>\r\n <div style=\"padding: 0 1em 1em 1em;text-align:right;\">\r\n <input style=\"height:1.65em;padding:0 0.75em;\" type=\"submit\" value=\"Find\"/>\r\n </div>\r\n </form>\r\n </div>\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".handleBox\").autocomplete(\"/data/handles\", {\r\n delay: 200,\r\n width: 200,\r\n selectFirst: false,\r\n matchContains: true,\r\n minChars: 3\r\n });\r\n $(\".handleForm\").attr(\"autocomplete\", \"off\").submit(function () {\r\n var link = \"/profile/userHandle\".replace(\r\n \"userHandle\", $(this).find(\".handleBox\").val()\r\n );\r\n window.location = link;\r\n return false;\r\n });\r\n });\n </script>\n\r\n\r\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Recent actions\n <div class=\"top-links\">\n </div>\n </div>\n <div class=\"recent-actions\">\r\n <ul>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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href=\"/profile/Seyaua\">Seyaua</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/Seyaua\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/Seyaua\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/Seyaua\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/Seyaua\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/Seyaua\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/Seyaua\" style=\"text-decoration:none;color:black !important;\">Seyaua's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"835\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/835\"> <p>Codeforces Beta Round #39 (Разбор задач)</p>\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/Seyaua\" title=\"Master Seyaua\" class=\"rated-user user-orange\">Seyaua</a>,\r\n <span class=\"format-humantime\" title=\"Nov/06/2010 23:53\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><b><div>Задача A. Определите цвет</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Здесь все понятно. Достаточно рассмотреть несколько случаев. Первый — когда расстояние от <b><div style=\"font-weight: normal;display: inline !important;\">точки до начала координат — целое число, тогда ответ black. В противном случае, пусть <span class=\"tex-span\"><i>d</i></span> </div></b><b><div style=\"font-weight: normal;display: inline !important;\">- это расстояние от нашей точки до начала координат. Тогда будем работать с <span class=\"tex-span\">[<i>d</i>]</span>. Теперь </div></b><b><div style=\"font-weight: normal;display: inline !important;\">осталось два случая: 1) если наша точка лежит в 1-ой, или 3-ей четверти; 2) точка лежит во </div></b><b><div style=\"font-weight: normal;display: inline !important;\">2-ой, либо 4-ой четверти. В случае 1) имеем, если <span class=\"tex-span\">[<i>d</i>]</span> нечетно, то ответ white, иначе </div></b><b><div style=\"font-weight: normal;display: inline !important;\">black; в случае 2) если <span class=\"tex-span\">[<i>d</i>]</span> четно, то ответ white, иначе black. Подразумевается, что </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\">[<i>d</i>]</span> — целая часть <span class=\"tex-span\"><i>d</i></span>.</div></b></div><div style=\"font-weight: normal;\"><br /></div><div>Задача B. Перекрашивания</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Первое, что надо заметить, так это то, что на i-ом шаге все перекрашенные клетки будут <b><div style=\"font-weight: normal;display: inline !important;\">лежать в прямоугольнике с вершинами в клетках (i,i), (n-i,m-i) (если считать, что (1,1) - </div></b><b><div style=\"font-weight: normal;display: inline !important;\">левая верхняя клетка, а (n,m) — правая нижняя). Тогда отсюда уже следует решение: нужно </div></b><b><div style=\"font-weight: normal;display: inline !important;\">подсчитать количество клеток такого типа, что минимальное расстояние до стороны в точности </div></b><b><div style=\"font-weight: normal;display: inline !important;\">равняется x. То есть для клетки (a,b) должно выполняться </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\"><i>min</i>(<i>min</i>(<i>a</i>, <i>b</i>), <i>min</i>(<i>n</i> - <i>a</i> + 1, <i>m</i> - <i>b</i> + 1)) = <i>x</i></span>.</div></b></div></b></div><div><b><br /></b></div><div><b>Задача C. Берляндская площадь</b></div><div><br /></div><div>Идейно эта задача не очень сложная, но было много хитрых случаев. Авторское решение предполагало следующую идею. Сначала заметим, что наше множество окружностей на плоскости может быть несвязным. Тут есть два случая, когда есть хотя бы одна точка пересечения окружностей и когда нет ни одной. Если их нет, то ответ N+M+1. Иначе, если есть хотя бы одна точка пересечения, то мы можем удалить некоторые окружности таким образом, чтобы оставшаяся фигура из окружностей была связной. Тогда для этой фигуры можно применить <a href=\"https://ru.wikipedia.org/wiki/Планарный_граф\">формулу Эйлера</a>. Таким образом, нам здесь нужно посчитать количество точек пересечения и количество дуг-ребер. Нетрудно видеть, что каждая точка пересечения добавляет две дуги. Таким образом, мы можем найти количество частей, на которые разделилась плоскость без удаленных окружностей. Теперь достаточно заметить, что каждая удаленная окружность добавляет ровно 1 к ответу. Весь вопрос в том, чтобы посчитать, сколько точек пересечения. Это можно сделать за O(N+M), если считать для каждой окружности, точки пересечения, которые принадлежат ей. Для этого достаточно заметить, что все окружности, с которыми наша окружность пересекается будут иметь радиусы l, l+1, ..., r. Также, с некоторыми из этих окружностей наша окружность будет иметь не две точки пересечения а одну. Это необходимо учесть в решении. После этого остается лишь аккуратно реализовать эту идею. </div><div><br /></div><div><b>Задача D. Интересная последовательность</b></div><div><br /></div><div>Здесь нужно было погенерировать разные последовательности, которые могут получаться и внимательно смотреть на полученные значения. Основное наблюдение, это то, что каждое из чисел, которые встречаются в последовательности имеет вид <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, при этом это число может встречаться лишь на позиции <span class=\"tex-span\">(<i>k</i> + <i>m</i> + 1)</span>. Теперь, когда известен общий вид, можно по методу математической индукции доказать, что на <span class=\"tex-span\"><i>x</i></span>-ой позиции могут встречаться все числа вида <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, такие что, <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span>. После этого можно было реализовать простое в написании решение за <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">3</sup>)</span>, где <span class=\"tex-span\"><i>N</i></span> — длина входного числа. Для этого перебираем все x от 1 до 600 и проверяем, существуют ли такие <span class=\"tex-span\"><i>k</i></span> и <span class=\"tex-span\"><i>m</i></span>, что <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span> и <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup> = <i>A</i></span>. Но также есть и решение со сложностью <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">2</sup>)</span>.</div><div><br /></div><div><b>Задача E. Таблица из чисел</b></div><div><br /></div><div>Первое, что должно было броситься в глаза, это то, что клеток, изначально не пустых — совсем мало. Из ограничений следует, что всегда есть пустая строка либо пустой столбец. Без ограничений общности можем считать, что у нас есть пустая строка и она последняя. Тогда выберем какой-либо столбец (к примеру, последний) и зафиксируем его одновременно с пустой строкой. Тогда по оставшейся таблице размера <span class=\"tex-span\">(<i>n</i> - 1) × (<i>m</i> - 1)</span> клетки в последнем столбце и в последней строке заполняются однозначно. Но есть одно замечание, в последнем столбце уже стоят какие-то числа. Тогда нам надо для каждой строки, кроме последней подсчитать, сколько существует вариантов этой строки, таких, что произведение чисел в этой строке равно -1. В авторском решении, эта часть считалась при помощи динамического программирования. После этого нужно перемножить полученные ответы для каждой строки. Тогда ответ на задачу — это полученное произведение, либо 0 — если сумма <span class=\"tex-span\"><i>n</i> + <i>m</i></span> нечетна.</div><div><br /></div> <div></div><div><br /></div>Разбор задач был подготовлен мной и <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/sdya\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Colonel sdya\">sdya</a></span>. </div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-140-835\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"140\",\n blogEntryId: \"835\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: 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Number Table"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Number Table</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>216 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>As it has been found out recently, all the Berland's current economical state can be described using a simple table <span class=\"tex-span\"><i>n</i> × <i>m</i></span> in size. <span class=\"tex-span\"><i>n</i></span> — the number of days in each Berland month, <span class=\"tex-span\"><i>m</i></span> — the number of months. Thus, a table cell corresponds to a day and a month of the Berland's year. Each cell will contain either <span class=\"tex-font-style-tt\">1</span>, or <span class=\"tex-font-style-tt\">-1</span>, which means the state's gains in a particular month, on a particular day. <span class=\"tex-font-style-tt\">1</span> corresponds to profits, <span class=\"tex-font-style-tt\">-1</span> corresponds to losses. It turned out important for successful development to analyze the data on the state of the economy of the previous year, however when the treasurers referred to the archives to retrieve the data, it turned out that the table had been substantially damaged. In some table cells the number values had faded and were impossible to be deciphered. It is known that the number of cells in which the data had been preserved is strictly less than <span class=\"tex-span\"><i>max</i>(<i>n</i>, <i>m</i>)</span>. However, there is additional information — the product of the numbers in each line and column equaled <span class=\"tex-font-style-tt\">-1</span>. Your task is to find out how many different tables may conform to the preserved data. As the answer to the task can be quite large, you have to find it modulo <span class=\"tex-span\"><i>p</i></span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 1000</span>). The second line contains the integer <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">0 ≤ <i>k</i> < <i>max</i>(<i>n</i>, <i>m</i>)</span>) — the number of cells in which the data had been preserved. The next <span class=\"tex-span\"><i>k</i></span> lines contain the data on the state of the table in the preserved cells. Each line is of the form \"<span class=\"tex-span\"><i>a</i></span> <span class=\"tex-span\"><i>b</i></span> <span class=\"tex-span\"><i>c</i></span>\", where <span class=\"tex-span\"><i>a</i></span> (<span class=\"tex-span\">1 ≤ <i>a</i> ≤ <i>n</i></span>) — the number of the table row, <span class=\"tex-span\"><i>b</i></span> (<span class=\"tex-span\">1 ≤ <i>b</i> ≤ <i>m</i></span>) — the number of the column, <span class=\"tex-span\"><i>c</i></span> — the value containing in the cell (<span class=\"tex-font-style-tt\">1</span> or <span class=\"tex-font-style-tt\">-1</span>). They are numbered starting from <span class=\"tex-span\">1</span>. It is guaranteed that no two lines with same <span class=\"tex-span\"><i>a</i></span> and <span class=\"tex-span\"><i>b</i></span> values exist. The last line contains an integer <span class=\"tex-span\"><i>p</i></span> (<span class=\"tex-span\">2 ≤ <i>p</i> ≤ 10<sup class=\"upper-index\">9</sup> + 7</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the number of different tables that could conform to the preserved data modulo <span class=\"tex-span\"><i>p</i></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2<br/>0<br/>100<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 2<br/>1<br/>1 1 -1<br/>100<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"a1155f6fe95b8b3adf5045d6a3d9f142\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"8f18df365110f9f39e201e49a37c61746b1357f8\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/40\">Codeforces Beta Round 39</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='a1155f6fe95b8b3adf5045d6a3d9f142'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/40/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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title=\"Codeforces Beta Round #39\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"160:161\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/835\" title=\"Codeforces Beta Round #39 (Разбор задач)\" target=\"_blank\">Tutorial #1 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"553\" resourceName=\"Codeforces Beta Round #39 (Разбор задач)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/829\" title=\"codeforces #39\" target=\"_blank\">codeforces #39 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"162\" resourceName=\"codeforces #39\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/40\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/40/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/40/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/40/status\">Status</a></li>\r\n <li><a\r\n 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result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"E\" data-uuid=\"ps_1d723f325bc19064060e16e0cf4b68c174cdbacc\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Number Table</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>216 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>As it has been found out recently, all the Berland's current economical state can be described using a simple table <span class=\"tex-span\"><i>n</i> × <i>m</i></span> in size. <span class=\"tex-span\"><i>n</i></span> — the number of days in each Berland month, <span class=\"tex-span\"><i>m</i></span> — the number of months. Thus, a table cell corresponds to a day and a month of the Berland's year. Each cell will contain either <span class=\"tex-font-style-tt\">1</span>, or <span class=\"tex-font-style-tt\">-1</span>, which means the state's gains in a particular month, on a particular day. <span class=\"tex-font-style-tt\">1</span> corresponds to profits, <span class=\"tex-font-style-tt\">-1</span> corresponds to losses. It turned out important for successful development to analyze the data on the state of the economy of the previous year, however when the treasurers referred to the archives to retrieve the data, it turned out that the table had been substantially damaged. In some table cells the number values had faded and were impossible to be deciphered. It is known that the number of cells in which the data had been preserved is strictly less than <span class=\"tex-span\"><i>max</i>(<i>n</i>, <i>m</i>)</span>. However, there is additional information — the product of the numbers in each line and column equaled <span class=\"tex-font-style-tt\">-1</span>. Your task is to find out how many different tables may conform to the preserved data. As the answer to the task can be quite large, you have to find it modulo <span class=\"tex-span\"><i>p</i></span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>n</i></span> and <span class=\"tex-span\"><i>m</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 1000</span>). The second line contains the integer <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">0 ≤ <i>k</i> < <i>max</i>(<i>n</i>, <i>m</i>)</span>) — the number of cells in which the data had been preserved. The next <span class=\"tex-span\"><i>k</i></span> lines contain the data on the state of the table in the preserved cells. Each line is of the form "<span class=\"tex-span\"><i>a</i></span> <span class=\"tex-span\"><i>b</i></span> <span class=\"tex-span\"><i>c</i></span>", where <span class=\"tex-span\"><i>a</i></span> (<span class=\"tex-span\">1 ≤ <i>a</i> ≤ <i>n</i></span>) — the number of the table row, <span class=\"tex-span\"><i>b</i></span> (<span class=\"tex-span\">1 ≤ <i>b</i> ≤ <i>m</i></span>) — the number of the column, <span class=\"tex-span\"><i>c</i></span> — the value containing in the cell (<span class=\"tex-font-style-tt\">1</span> or <span class=\"tex-font-style-tt\">-1</span>). They are numbered starting from <span class=\"tex-span\">1</span>. It is guaranteed that no two lines with same <span class=\"tex-span\"><i>a</i></span> and <span class=\"tex-span\"><i>b</i></span> values exist. The last line contains an integer <span class=\"tex-span\"><i>p</i></span> (<span class=\"tex-span\">2 ≤ <i>p</i> ≤ 10<sup class=\"upper-index\">9</sup> + 7</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the number of different tables that could conform to the preserved data modulo <span class=\"tex-span\"><i>p</i></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2<br />0<br />100<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 2<br />1<br />1 1 -1<br />100<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:57:03</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='a2448587f0b0309e076af46c2a86694c'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/Seyaua\">Seyaua</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/Seyaua\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/Seyaua\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/Seyaua\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/Seyaua\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/Seyaua\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/Seyaua\" style=\"text-decoration:none;color:black !important;\">Seyaua's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"835\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/835\"> <p>Codeforces Beta Round #39 (Разбор задач)</p>\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/Seyaua\" title=\"Master Seyaua\" class=\"rated-user user-orange\">Seyaua</a>,\r\n <span class=\"format-humantime\" title=\"Nov/06/2010 23:53\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><b><div>Задача A. Определите цвет</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Здесь все понятно. Достаточно рассмотреть несколько случаев. Первый — когда расстояние от <b><div style=\"font-weight: normal;display: inline !important;\">точки до начала координат — целое число, тогда ответ black. В противном случае, пусть <span class=\"tex-span\"><i>d</i></span> </div></b><b><div style=\"font-weight: normal;display: inline !important;\">- это расстояние от нашей точки до начала координат. Тогда будем работать с <span class=\"tex-span\">[<i>d</i>]</span>. Теперь </div></b><b><div style=\"font-weight: normal;display: inline !important;\">осталось два случая: 1) если наша точка лежит в 1-ой, или 3-ей четверти; 2) точка лежит во </div></b><b><div style=\"font-weight: normal;display: inline !important;\">2-ой, либо 4-ой четверти. В случае 1) имеем, если <span class=\"tex-span\">[<i>d</i>]</span> нечетно, то ответ white, иначе </div></b><b><div style=\"font-weight: normal;display: inline !important;\">black; в случае 2) если <span class=\"tex-span\">[<i>d</i>]</span> четно, то ответ white, иначе black. Подразумевается, что </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\">[<i>d</i>]</span> — целая часть <span class=\"tex-span\"><i>d</i></span>.</div></b></div><div style=\"font-weight: normal;\"><br /></div><div>Задача B. Перекрашивания</div><div style=\"font-weight: normal;\"><br /></div><div style=\"font-weight: normal;\">Первое, что надо заметить, так это то, что на i-ом шаге все перекрашенные клетки будут <b><div style=\"font-weight: normal;display: inline !important;\">лежать в прямоугольнике с вершинами в клетках (i,i), (n-i,m-i) (если считать, что (1,1) - </div></b><b><div style=\"font-weight: normal;display: inline !important;\">левая верхняя клетка, а (n,m) — правая нижняя). Тогда отсюда уже следует решение: нужно </div></b><b><div style=\"font-weight: normal;display: inline !important;\">подсчитать количество клеток такого типа, что минимальное расстояние до стороны в точности </div></b><b><div style=\"font-weight: normal;display: inline !important;\">равняется x. То есть для клетки (a,b) должно выполняться </div></b><b><div style=\"font-weight: normal;display: inline !important;\"><span class=\"tex-span\"><i>min</i>(<i>min</i>(<i>a</i>, <i>b</i>), <i>min</i>(<i>n</i> - <i>a</i> + 1, <i>m</i> - <i>b</i> + 1)) = <i>x</i></span>.</div></b></div></b></div><div><b><br /></b></div><div><b>Задача C. Берляндская площадь</b></div><div><br /></div><div>Идейно эта задача не очень сложная, но было много хитрых случаев. Авторское решение предполагало следующую идею. Сначала заметим, что наше множество окружностей на плоскости может быть несвязным. Тут есть два случая, когда есть хотя бы одна точка пересечения окружностей и когда нет ни одной. Если их нет, то ответ N+M+1. Иначе, если есть хотя бы одна точка пересечения, то мы можем удалить некоторые окружности таким образом, чтобы оставшаяся фигура из окружностей была связной. Тогда для этой фигуры можно применить <a href=\"https://ru.wikipedia.org/wiki/Планарный_граф\">формулу Эйлера</a>. Таким образом, нам здесь нужно посчитать количество точек пересечения и количество дуг-ребер. Нетрудно видеть, что каждая точка пересечения добавляет две дуги. Таким образом, мы можем найти количество частей, на которые разделилась плоскость без удаленных окружностей. Теперь достаточно заметить, что каждая удаленная окружность добавляет ровно 1 к ответу. Весь вопрос в том, чтобы посчитать, сколько точек пересечения. Это можно сделать за O(N+M), если считать для каждой окружности, точки пересечения, которые принадлежат ей. Для этого достаточно заметить, что все окружности, с которыми наша окружность пересекается будут иметь радиусы l, l+1, ..., r. Также, с некоторыми из этих окружностей наша окружность будет иметь не две точки пересечения а одну. Это необходимо учесть в решении. После этого остается лишь аккуратно реализовать эту идею. </div><div><br /></div><div><b>Задача D. Интересная последовательность</b></div><div><br /></div><div>Здесь нужно было погенерировать разные последовательности, которые могут получаться и внимательно смотреть на полученные значения. Основное наблюдение, это то, что каждое из чисел, которые встречаются в последовательности имеет вид <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, при этом это число может встречаться лишь на позиции <span class=\"tex-span\">(<i>k</i> + <i>m</i> + 1)</span>. Теперь, когда известен общий вид, можно по методу математической индукции доказать, что на <span class=\"tex-span\"><i>x</i></span>-ой позиции могут встречаться все числа вида <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup></span>, такие что, <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span>. После этого можно было реализовать простое в написании решение за <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">3</sup>)</span>, где <span class=\"tex-span\"><i>N</i></span> — длина входного числа. Для этого перебираем все x от 1 до 600 и проверяем, существуют ли такие <span class=\"tex-span\"><i>k</i></span> и <span class=\"tex-span\"><i>m</i></span>, что <span class=\"tex-span\"><i>k</i> + <i>m</i> + 1 = <i>x</i></span> и <span class=\"tex-span\">12<sup class=\"upper-index\"><i>k</i></sup> + 12<sup class=\"upper-index\"><i>m</i></sup> = <i>A</i></span>. Но также есть и решение со сложностью <span class=\"tex-span\"><i>O</i>(<i>N</i><sup class=\"upper-index\">2</sup>)</span>.</div><div><br /></div><div><b>Задача E. Таблица из чисел</b></div><div><br /></div><div>Первое, что должно было броситься в глаза, это то, что клеток, изначально не пустых — совсем мало. Из ограничений следует, что всегда есть пустая строка либо пустой столбец. Без ограничений общности можем считать, что у нас есть пустая строка и она последняя. Тогда выберем какой-либо столбец (к примеру, последний) и зафиксируем его одновременно с пустой строкой. Тогда по оставшейся таблице размера <span class=\"tex-span\">(<i>n</i> - 1) × (<i>m</i> - 1)</span> клетки в последнем столбце и в последней строке заполняются однозначно. Но есть одно замечание, в последнем столбце уже стоят какие-то числа. Тогда нам надо для каждой строки, кроме последней подсчитать, сколько существует вариантов этой строки, таких, что произведение чисел в этой строке равно -1. В авторском решении, эта часть считалась при помощи динамического программирования. После этого нужно перемножить полученные ответы для каждой строки. Тогда ответ на задачу — это полученное произведение, либо 0 — если сумма <span class=\"tex-span\"><i>n</i> + <i>m</i></span> нечетна.</div><div><br /></div> <div></div><div><br /></div>Разбор задач был подготовлен мной и <span style=\"border-collapse: collapse;font-family: verdana , arial , sans-serif;font-size: 13.0px;\"><a class=\"rated-user user-red\" href=\"https://codeforces.com/profile/sdya\" style=\"font-family: arial;text-decoration: none !important;font-weight: bold;color: rgb(0,0,204);\" title=\"Colonel sdya\">sdya</a></span>. </div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-140-835\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"140\",\n blogEntryId: \"835\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: 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problem_id stringlengths 2 6 | contest stringlengths 1 4 | problem stringlengths 1 3 | lang stringclasses 2
values | problem_title stringlengths 0 63 | problem_statement stringlengths 0 13.7k | page stringlengths 11.2k 95.4k | long_tags stringlengths 2 1.79k | short_tags stringlengths 2 657 | tutorial_link stringlengths 0 87 | tutorial_page stringlengths 0 1.22M |
|---|---|---|---|---|---|---|---|---|---|---|
22E | 22 | E | en | E. Scheme | <div class="problem-statement"><div class="header"><div class="title">E. Scheme</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="00315a1861bbfb2cb159f26acd715460"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dfs and similar", "Graphs", "Trees"] | ["dfs and similar", "graphs", "trees", "*2300"] | https://codeforces.com/blog/entry/507 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="24bfa389977bffbbea433287f885534f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
23A | 23 | A | en | A. You're Given a String... | <div class="problem-statement"><div class="header"><div class="title">A. You're Given a String...</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7c01a0157132171e4c00945f96fb9c69"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Greedy algorithms"] | ["brute force", "greedy", "*1200"] | https://codeforces.com/blog/entry/530 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8a8e7336bb6509c6a4a1ee30b5ecd3aa"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
23B | 23 | B | en | B. Party | <div class="problem-statement"><div class="header"><div class="title">B. Party</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="81ed1c6e58d5a220e05872663011df0d"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Graphs", "Mathematics including integration, differential equations, etc"] | ["constructive algorithms", "graphs", "math", "*1600"] | https://codeforces.com/blog/entry/530 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8a8e7336bb6509c6a4a1ee30b5ecd3aa"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
23C | 23 | C | en | C. Oranges and Apples | <div class="problem-statement"><div class="header"><div class="title">C. Oranges and Apples</div><div class="time-limit"><div class="property-title">time limit per test</div>1.5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div ... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1a94f963a54fbc996a741f08b897b861"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Sortings, orderings"] | ["constructive algorithms", "sortings", "*2500"] | https://codeforces.com/blog/entry/530 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8a8e7336bb6509c6a4a1ee30b5ecd3aa"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
23D | 23 | D | en | D. Tetragon | <div class="problem-statement"><div class="header"><div class="title">D. Tetragon</div><div class="time-limit"><div class="property-title">time limit per test</div>3 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="16c259bb08b70cd1d82e840ae45a586d"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry", "Mathematics including integration, differential equations, etc"] | ["geometry", "math", "*2600"] | https://codeforces.com/blog/entry/530 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8a8e7336bb6509c6a4a1ee30b5ecd3aa"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
23E | 23 | E | en | E. Tree | <div class="problem-statement"><div class="header"><div class="title">E. Tree</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1c012afe009dc236c8e87095674f833a"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming"] | ["dp", "*2500"] | https://codeforces.com/blog/entry/530 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8a8e7336bb6509c6a4a1ee30b5ecd3aa"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
24A | 24 | A | en | A. Ring road | <div class="problem-statement"><div class="header"><div class="title">A. Ring road</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7671fb5c94aac87263da43f4e385ffb4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Graphs"] | ["graphs", "*1400"] | https://codeforces.com/blog/entry/557 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6ab234d82c1f4b7477b15d9e8c982324"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
24B | 24 | B | en | B. F1 Champions | <div class="problem-statement"><div class="header"><div class="title">B. F1 Champions</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6d0ed45433cdee541ee74118566780ea"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1500"] | https://codeforces.com/blog/entry/557 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6ab234d82c1f4b7477b15d9e8c982324"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
24C | 24 | C | en | C. Sequence of points | <div class="problem-statement"><div class="header"><div class="title">C. Sequence of points</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cl... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="d4679f6ac1c56bade0d725a2d2646ee4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry", "Implementation problems, programming technics, simulation", "Mathematics including integration, differential equations, etc"] | ["geometry", "implementation", "math", "*1800"] | https://codeforces.com/blog/entry/557 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6ab234d82c1f4b7477b15d9e8c982324"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
24D | 24 | D | en | D. Broken robot | <div class="problem-statement"><div class="header"><div class="title">D. Broken robot</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b1824499c943ec6d45ff7814d5b30276"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Mathematics including integration, differential equations, etc", "Probabilities, expected values, statistics, random variables, etc"] | ["dp", "math", "probabilities", "*2400"] | https://codeforces.com/blog/entry/557 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6ab234d82c1f4b7477b15d9e8c982324"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
24E | 24 | E | en | E. Berland collider | <div class="problem-statement"><div class="header"><div class="title">E. Berland collider</div><div class="time-limit"><div class="property-title">time limit per test</div>1.5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cl... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="380da92890e5696ba4a3cc1b32d920e6"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Binary search"] | ["binary search", "*2300"] | https://codeforces.com/blog/entry/557 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6ab234d82c1f4b7477b15d9e8c982324"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
25A | 25 | A | en | A. IQ test | <div class="problem-statement"><div class="header"><div class="title">A. IQ test</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="proper... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6e533fd00fba0bc58459fa3e313361de"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force"] | ["brute force", "*1300"] | https://codeforces.com/blog/entry/594 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="936d4a3202a103a98010298f4ddde342"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
25B | 25 | B | en | B. Phone numbers | <div class="problem-statement"><div class="header"><div class="title">B. Phone numbers</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="04694c6e2f113649e92fa74f6ea5e2ff"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1100"] | https://codeforces.com/blog/entry/594 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="936d4a3202a103a98010298f4ddde342"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
25C | 25 | C | en | C. Roads in Berland | <div class="problem-statement"><div class="header"><div class="title">C. Roads in Berland</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div clas... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5dfeb87ac6e6404940b45f8904cc6352"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Graphs", "Shortest paths on weighted and unweighted graphs"] | ["graphs", "shortest paths", "*1900"] | https://codeforces.com/blog/entry/594 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="936d4a3202a103a98010298f4ddde342"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
25D | 25 | D | en | D. Roads not only in Berland | <div class="problem-statement"><div class="header"><div class="title">D. Roads not only in Berland</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file">... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="c18df0438c2db04c06b00de051cd153b"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Disjoint set union", "Graphs", "Trees"] | ["dsu", "graphs", "trees", "*1900"] | https://codeforces.com/blog/entry/594 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="936d4a3202a103a98010298f4ddde342"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
25E | 25 | E | en | E. Test | <div class="problem-statement"><div class="header"><div class="title">E. Test</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="c741be3251686f97511983c33872d43c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Hashing, hashtables", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["hashing", "strings", "*2200"] | https://codeforces.com/blog/entry/594 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="936d4a3202a103a98010298f4ddde342"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
26A | 26 | A | en | A. Almost Prime | <div class="problem-statement"><div class="header"><div class="title">A. Almost Prime</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1c1f9453dd2176f1fe8c4a315b53bc29"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Number theory: Euler function, GCD, divisibility, etc"] | ["number theory", "*900"] | https://codeforces.com/blog/entry/610 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="164e5ebfa32c8627604f12b27992e78c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
26B | 26 | B | en | B. Regular Bracket Sequence | <div class="problem-statement"><div class="header"><div class="title">B. Regular Bracket Sequence</div><div class="time-limit"><div class="property-title">time limit per test</div>5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ede93783e6af9111495fe2ec718b15a4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms"] | ["greedy", "*1400"] | https://codeforces.com/blog/entry/610 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="164e5ebfa32c8627604f12b27992e78c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
26C | 26 | C | en | C. Parquet | <div class="problem-statement"><div class="header"><div class="title">C. Parquet</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="proper... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a6184a4b0983f795a95957972fa2a0bc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Combinatorics", "Constructive algorithms", "Greedy algorithms", "Implementation problems, programming technics, simulation"] | ["combinatorics", "constructive algorithms", "greedy", "implementation", "*2000"] | https://codeforces.com/blog/entry/610 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="164e5ebfa32c8627604f12b27992e78c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
26D | 26 | D | en | D. Tickets | <div class="problem-statement"><div class="header"><div class="title">D. Tickets</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="proper... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9d2ab099109cf0311b2582d2f9be2831"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Combinatorics", "Mathematics including integration, differential equations, etc", "Probabilities, expected values, statistics, random variables, etc"] | ["combinatorics", "math", "probabilities", "*2400"] | https://codeforces.com/blog/entry/610 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="164e5ebfa32c8627604f12b27992e78c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
26E | 26 | E | en | E. Multithreading | <div class="problem-statement"><div class="header"><div class="title">E. Multithreading</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="28a07fe98e36e0ff6138f2e52abd3360"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms"] | ["constructive algorithms", "*2400"] | https://codeforces.com/blog/entry/610 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="164e5ebfa32c8627604f12b27992e78c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
27A | 27 | A | en | A. Next Test | <div class="problem-statement"><div class="header"><div class="title">A. Next Test</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="255f75a01bee10a250f6147096191668"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation", "Sortings, orderings"] | ["implementation", "sortings", "*1200"] | https://codeforces.com/blog/entry/653 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="84d4ffc798052f6178c102d9883d4f11"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
27B | 27 | B | en | B. Tournament | <div class="problem-statement"><div class="header"><div class="title">B. Tournament</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pro... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="497ab6c68d75096615eb0d82687eac73"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Bitmasks", "Brute force", "Dfs and similar", "Greedy algorithms"] | ["bitmasks", "brute force", "dfs and similar", "greedy", "*1300"] | https://codeforces.com/blog/entry/653 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="84d4ffc798052f6178c102d9883d4f11"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
27C | 27 | C | en | C. Unordered Subsequence | <div class="problem-statement"><div class="header"><div class="title">C. Unordered Subsequence</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="88ddecf129363bc7c411586514e5f155"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Greedy algorithms"] | ["constructive algorithms", "greedy", "*1900"] | https://codeforces.com/blog/entry/653 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="84d4ffc798052f6178c102d9883d4f11"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
27D | 27 | D | en | D. Ring Road 2 | <div class="problem-statement"><div class="header"><div class="title">D. Ring Road 2</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="00174b3c8485298e3bbf3b4464356bed"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["2-satisfiability", "Dfs and similar", "Disjoint set union", "Graphs"] | ["2-sat", "dfs and similar", "dsu", "graphs", "*2200"] | https://codeforces.com/blog/entry/653 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="84d4ffc798052f6178c102d9883d4f11"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
27E | 27 | E | en | E. Number With The Given Amount Of Divisors | <div class="problem-statement"><div class="header"><div class="title">E. Number With The Given Amount Of Divisors</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div clas... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f65b4dd55443000123fd81f4e30dfe86"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Dynamic programming", "Number theory: Euler function, GCD, divisibility, etc"] | ["brute force", "dp", "number theory", "*2000"] | https://codeforces.com/blog/entry/653 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="84d4ffc798052f6178c102d9883d4f11"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
28A | 28 | A | en | A. Bender Problem | <div class="problem-statement"><div class="header"><div class="title">A. Bender Problem</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="53ea3e2978f5a56cdd4da254fa7c4dce"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1600"] | https://codeforces.com/blog/entry/685 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4c40360a1117d6f4be8125e7cb386ffc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
28B | 28 | B | en | B. pSort | <div class="problem-statement"><div class="header"><div class="title">B. pSort</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="c37a01d6ccce937a399aa066f4877bd7"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dfs and similar", "Disjoint set union", "Graphs"] | ["dfs and similar", "dsu", "graphs", "*1600"] | https://codeforces.com/blog/entry/685 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4c40360a1117d6f4be8125e7cb386ffc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
28C | 28 | C | en | C. Bath Queue | <div class="problem-statement"><div class="header"><div class="title">C. Bath Queue</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pro... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2b6a887c101740c1b4e6cb7fb2af3f6b"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Combinatorics", "Dynamic programming", "Probabilities, expected values, statistics, random variables, etc"] | ["combinatorics", "dp", "probabilities", "*2200"] | https://codeforces.com/blog/entry/685 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4c40360a1117d6f4be8125e7cb386ffc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
28D | 28 | D | en | D. Don't fear, DravDe is kind | <div class="problem-statement"><div class="header"><div class="title">D. Don't fear, DravDe is kind</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="750df012dfba048d150e23a49b5b6cf9"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Binary search", "Heaps, binary search trees, segment trees, hash tables, etc", "Dynamic programming", "Hashing, hashtables"] | ["binary search", "data structures", "dp", "hashing", "*2400"] | https://codeforces.com/blog/entry/685 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4c40360a1117d6f4be8125e7cb386ffc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
28E | 28 | E | en | E. DravDe saves the world | <div class="problem-statement"><div class="header"><div class="title">E. DravDe saves the world</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a0378815c549098acfeea269db353830"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry", "Mathematics including integration, differential equations, etc"] | ["geometry", "math", "*2800"] | https://codeforces.com/blog/entry/685 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4c40360a1117d6f4be8125e7cb386ffc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
29A | 29 | A | en | A. Spit Problem | <div class="problem-statement"><div class="header"><div class="title">A. Spit Problem</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5704a209ba5c868d481f3cd070c08fe4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force"] | ["brute force", "*1000"] | https://codeforces.com/blog/entry/686 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="13a7cf33a37565d2e709ff9c00c4fee4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
29B | 29 | B | en | B. Traffic Lights | <div class="problem-statement"><div class="header"><div class="title">B. Traffic Lights</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="999d101ed35485909fcdcd352aa0d5cc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1500"] | https://codeforces.com/blog/entry/686 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="13a7cf33a37565d2e709ff9c00c4fee4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
29C | 29 | C | en | C. Mail Stamps | <div class="problem-statement"><div class="header"><div class="title">C. Mail Stamps</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="57ed6e372482ad7c8704803e7e12f5df"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc", "Dfs and similar", "Graphs", "Implementation problems, programming technics, simulation"] | ["data structures", "dfs and similar", "graphs", "implementation", "*1700"] | https://codeforces.com/blog/entry/686 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="13a7cf33a37565d2e709ff9c00c4fee4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
29D | 29 | D | en | D. Ant on the Tree | <div class="problem-statement"><div class="header"><div class="title">D. Ant on the Tree</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a2f5f1abe1dfa0ed8e1c844ace144be9"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Dfs and similar", "Trees"] | ["constructive algorithms", "dfs and similar", "trees", "*2000"] | https://codeforces.com/blog/entry/686 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="13a7cf33a37565d2e709ff9c00c4fee4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
29E | 29 | E | en | E. Quarrel | <div class="problem-statement"><div class="header"><div class="title">E. Quarrel</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="357d75f73e22a9e6aa1dec4fee33e4e8"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Graphs", "Shortest paths on weighted and unweighted graphs"] | ["graphs", "shortest paths", "*2400"] | https://codeforces.com/blog/entry/686 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="13a7cf33a37565d2e709ff9c00c4fee4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
30A | 30 | A | en | A. Accounting | <div class="problem-statement"><div class="header"><div class="title">A. Accounting</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pro... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="dec59c7ffe7e48dbca4397e28daf5936"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Mathematics including integration, differential equations, etc"] | ["brute force", "math", "*1400"] | https://codeforces.com/blog/entry/696 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ef24bbb6aa41eb06f07fc85909c1ad13"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
30B | 30 | B | en | B. Codeforces World Finals | <div class="problem-statement"><div class="header"><div class="title">B. Codeforces World Finals</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><d... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="cca37d0099420163b5c50ff950682528"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1700"] | https://codeforces.com/blog/entry/696 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ef24bbb6aa41eb06f07fc85909c1ad13"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
30C | 30 | C | en | C. Shooting Gallery | <div class="problem-statement"><div class="header"><div class="title">C. Shooting Gallery</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div clas... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7265b7ef7a82768afd7235edf3616457"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Probabilities, expected values, statistics, random variables, etc"] | ["dp", "probabilities", "*1800"] | https://codeforces.com/blog/entry/696 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ef24bbb6aa41eb06f07fc85909c1ad13"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
30D | 30 | D | en | D. King's Problem? | <div class="problem-statement"><div class="header"><div class="title">D. King's Problem?</div><div class="time-limit"><div class="property-title">time limit per test</div>3 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f69c38ecae681e197e11bcca36604732"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry", "Greedy algorithms"] | ["geometry", "greedy", "*2600"] | https://codeforces.com/blog/entry/696 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ef24bbb6aa41eb06f07fc85909c1ad13"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
30E | 30 | E | en | E. Tricky and Clever Password | <div class="problem-statement"><div class="header"><div class="title">E. Tricky and Clever Password</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4bdf2876e67b2dc1aef6dabeac5ecf02"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Binary search", "Constructive algorithms", "Heaps, binary search trees, segment trees, hash tables, etc", "Greedy algorithms", "Hashing, hashtables", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["binary search", "constructive algorithms", "data structures", "greedy", "hashing", "strings", "*2800"] | https://codeforces.com/blog/entry/696 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ef24bbb6aa41eb06f07fc85909c1ad13"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
31A | 31 | A | en | A. Worms Evolution | <div class="problem-statement"><div class="header"><div class="title">A. Worms Evolution</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="08663515416e1e9fa0466bc884197602"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1200"] | ||
31B | 31 | B | en | B. Sysadmin Bob | <div class="problem-statement"><div class="header"><div class="title">B. Sysadmin Bob</div><div class="time-limit"><div class="property-title">time limit per test</div>0.5 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="3439f3e68dc749fa7f524d2eda21071b"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms", "Implementation problems, programming technics, simulation", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["greedy", "implementation", "strings", "*1500"] | ||
31C | 31 | C | en | C. Schedule | <div class="problem-statement"><div class="header"><div class="title">C. Schedule</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="532228d20903ff999180c00ba122f8d6"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1700"] | ||
31D | 31 | D | en | D. Chocolate | <div class="problem-statement"><div class="header"><div class="title">D. Chocolate</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="72f2e593ce26e98a042b5d34d7b967d3"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dfs and similar", "Implementation problems, programming technics, simulation"] | ["dfs and similar", "implementation", "*2000"] | ||
31E | 31 | E | en | E. TV Game | <div class="problem-statement"><div class="header"><div class="title">E. TV Game</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="proper... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="654fa039a04cb3f5f9c13874a8272325"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming"] | ["dp", "*2400"] | ||
32A | 32 | A | en | A. Reconnaissance | <div class="problem-statement"><div class="header"><div class="title">A. Reconnaissance</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9150fc0fe05084a0985cf7b6716cffb2"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force"] | ["brute force", "*800"] | ||
32B | 32 | B | en | B. Borze | <div class="problem-statement"><div class="header"><div class="title">B. Borze</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="082ea81ee5202cacb74d9f164621a976"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Parsing expression grammar", "Implementation problems, programming technics, simulation"] | ["expression parsing", "implementation", "*800"] | ||
32C | 32 | C | en | C. Flea | <div class="problem-statement"><div class="header"><div class="title">C. Flea</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="e1e116329a3ea7ad876f21878d8eccc2"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Mathematics including integration, differential equations, etc"] | ["math", "*1700"] | ||
32D | 32 | D | en | D. Constellation | <div class="problem-statement"><div class="header"><div class="title">D. Constellation</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a9dbc5a11a579ed89ef4a3bb1e2562b5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1600"] | ||
32E | 32 | E | en | E. Hide-and-Seek | <div class="problem-statement"><div class="header"><div class="title">E. Hide-and-Seek</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="71fd1042ea8496d1edb49ba09717f3cd"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry", "Implementation problems, programming technics, simulation"] | ["geometry", "implementation", "*2400"] | ||
33A | 33 | A | en | A. What is for dinner? | <div class="problem-statement"><div class="header"><div class="title">A. What is for dinner?</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div c... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="126c531a8e171cfac3bad0cf36e40af6"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms", "Implementation problems, programming technics, simulation"] | ["greedy", "implementation", "*1200"] | https://codeforces.com/blog/entry/731 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="fca530187dc64c0b4bfbb21eff75eaf2"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
33B | 33 | B | en | B. String Problem | <div class="problem-statement"><div class="header"><div class="title">B. String Problem</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="175106110de377b2c32c18c2e0b9bbee"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Shortest paths on weighted and unweighted graphs"] | ["shortest paths", "*1800"] | https://codeforces.com/blog/entry/731 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="fca530187dc64c0b4bfbb21eff75eaf2"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
33C | 33 | C | en | C. Wonderful Randomized Sum | <div class="problem-statement"><div class="header"><div class="title">C. Wonderful Randomized Sum</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="e2d15e949b41beba7446f7e2d3093946"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms"] | ["greedy", "*1800"] | https://codeforces.com/blog/entry/731 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="fca530187dc64c0b4bfbb21eff75eaf2"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
33D | 33 | D | en | D. Knights | <div class="problem-statement"><div class="header"><div class="title">D. Knights</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="proper... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="edc78069cbf9aa4d796df93252b016dd"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry", "Graphs", "Shortest paths on weighted and unweighted graphs", "Sortings, orderings"] | ["geometry", "graphs", "shortest paths", "sortings", "*2000"] | https://codeforces.com/blog/entry/731 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="fca530187dc64c0b4bfbb21eff75eaf2"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
33E | 33 | E | en | E. Helper | <div class="problem-statement"><div class="header"><div class="title">E. Helper</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7803c05cf79ead7185754a4da0841c57"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | [] | ["*2600"] | https://codeforces.com/blog/entry/731 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="fca530187dc64c0b4bfbb21eff75eaf2"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
34A | 34 | A | en | A. Reconnaissance 2 | <div class="problem-statement"><div class="header"><div class="title">A. Reconnaissance 2</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div clas... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="13071c981676557a6b8edc00fcaa90bb"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*800"] | https://codeforces.com/blog/entry/748 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1728cbaec0e8d4cfb09d299a33fc492a"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
34B | 34 | B | en | B. Sale | <div class="problem-statement"><div class="header"><div class="title">B. Sale</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="581c8093391551f817561e73b26e6367"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms", "Sortings, orderings"] | ["greedy", "sortings", "*900"] | https://codeforces.com/blog/entry/748 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1728cbaec0e8d4cfb09d299a33fc492a"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
34C | 34 | C | en | C. Page Numbers | <div class="problem-statement"><div class="header"><div class="title">C. Page Numbers</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7355f40b32f9c3c1d93030515186969e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Parsing expression grammar", "Implementation problems, programming technics, simulation", "Sortings, orderings", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["expression parsing", "implementation", "sortings", "strings", "*1300"] | https://codeforces.com/blog/entry/748 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1728cbaec0e8d4cfb09d299a33fc492a"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
34D | 34 | D | en | D. Road Map | <div class="problem-statement"><div class="header"><div class="title">D. Road Map</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1066f0dbc55e594859dae1decba04385"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dfs and similar", "Graphs"] | ["dfs and similar", "graphs", "*1600"] | https://codeforces.com/blog/entry/748 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1728cbaec0e8d4cfb09d299a33fc492a"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
34E | 34 | E | en | E. Collisions | <div class="problem-statement"><div class="header"><div class="title">E. Collisions</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pro... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1f86ad8373e7707374a8502601e7a9d9"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Implementation problems, programming technics, simulation", "Mathematics including integration, differential equations, etc"] | ["brute force", "implementation", "math", "*2000"] | https://codeforces.com/blog/entry/748 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1728cbaec0e8d4cfb09d299a33fc492a"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
35A | 35 | A | en | A. Shell Game | <div class="problem-statement"><div class="header"><div class="title">A. Shell Game</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0c073369489706e6ad4400460d8fee76"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1000"] | ||
35B | 35 | B | en | B. Warehouse | <div class="problem-statement"><div class="header"><div class="title">B. Warehouse</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="455df1a2d395d6ce21d0dd5f1d774a16"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1700"] | ||
35C | 35 | C | en | C. Fire Again | <div class="problem-statement"><div class="header"><div class="title">C. Fire Again</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ba213a6e03040e4919c1bc183c3ae49d"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Dfs and similar", "Shortest paths on weighted and unweighted graphs"] | ["brute force", "dfs and similar", "shortest paths", "*1500"] | ||
35D | 35 | D | en | D. Animals | <div class="problem-statement"><div class="header"><div class="title">D. Animals</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5101bfdad72920c100b148c49218ec50"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Greedy algorithms"] | ["dp", "greedy", "*1700"] | ||
35E | 35 | E | en | E. Parade | <div class="problem-statement"><div class="header"><div class="title">E. Parade</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="property... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6b3ca0226a43d3b13fdb8eb974d187bd"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc", "Sortings, orderings"] | ["data structures", "sortings", "*2100"] | ||
36A | 36 | A | en | A. Extra-terrestrial Intelligence | <div class="problem-statement"><div class="header"><div class="title">A. Extra-terrestrial Intelligence</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-fi... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f886fbd775c2efd4bb4a973c0b94efe2"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1300"] | https://codeforces.com/blog/entry/773 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="bff5795e736ba9c233174f60d8665e4c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
36B | 36 | B | en | B. Fractal | <div class="problem-statement"><div class="header"><div class="title">B. Fractal</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b0133d446da8f6784979ac257ee11391"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1600"] | https://codeforces.com/blog/entry/773 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="bff5795e736ba9c233174f60d8665e4c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
36C | 36 | C | en | C. Bowls | <div class="problem-statement"><div class="header"><div class="title">C. Bowls</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2b1564ccec195f8d998d2dc7b465aad0"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry", "Implementation problems, programming technics, simulation"] | ["geometry", "implementation", "*2200"] | https://codeforces.com/blog/entry/773 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="bff5795e736ba9c233174f60d8665e4c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
36D | 36 | D | en | D. New Game with a Chess Piece | <div class="problem-statement"><div class="header"><div class="title">D. New Game with a Chess Piece</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="48b4490ce32b1e26ef6d823e725aba64"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Games, Sprague\u2013Grundy theorem"] | ["games", "*2300"] | https://codeforces.com/blog/entry/773 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="bff5795e736ba9c233174f60d8665e4c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
36E | 36 | E | en | E. Two Paths | <div class="problem-statement"><div class="header"><div class="title">E. Two Paths</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8cd8617b08a2b19cc1e01ffcdbca0795"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Disjoint set union", "Graphs", "Implementation problems, programming technics, simulation"] | ["constructive algorithms", "dsu", "graphs", "implementation", "*2600"] | https://codeforces.com/blog/entry/773 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="bff5795e736ba9c233174f60d8665e4c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
37A | 37 | A | en | A. Towers | <div class="problem-statement"><div class="header"><div class="title">A. Towers</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7303d7438efcdd19abc6a30c8c27a6ea"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Sortings, orderings"] | ["sortings", "*1000"] | https://codeforces.com/blog/entry/798 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0ab0f791e5640a29e183082a8066264f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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37B | 37 | B | en | B. Computer Game | <div class="problem-statement"><div class="header"><div class="title">B. Computer Game</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7691c07f7f00067ef227c09192fdc813"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms", "Implementation problems, programming technics, simulation"] | ["greedy", "implementation", "*1800"] | https://codeforces.com/blog/entry/798 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0ab0f791e5640a29e183082a8066264f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
37C | 37 | C | en | C. Old Berland Language | <div class="problem-statement"><div class="header"><div class="title">C. Old Berland Language</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div ... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0c616dd1b16779bdca7fe1e0b5add854"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc", "Greedy algorithms", "Trees"] | ["data structures", "greedy", "trees", "*1900"] | https://codeforces.com/blog/entry/798 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0ab0f791e5640a29e183082a8066264f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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37D | 37 | D | en | D. Lesson Timetable | <div class="problem-statement"><div class="header"><div class="title">D. Lesson Timetable</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a0500f9eada23626b9f086d2c85cba65"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Combinatorics", "Dynamic programming", "Mathematics including integration, differential equations, etc"] | ["combinatorics", "dp", "math", "*2300"] | https://codeforces.com/blog/entry/798 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0ab0f791e5640a29e183082a8066264f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
37E | 37 | E | en | E. Trial for Chief | <div class="problem-statement"><div class="header"><div class="title">E. Trial for Chief</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0aa140172e44edad1c329f942b62fd37"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Graphs", "Greedy algorithms", "Shortest paths on weighted and unweighted graphs"] | ["graphs", "greedy", "shortest paths", "*2600"] | https://codeforces.com/blog/entry/798 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0ab0f791e5640a29e183082a8066264f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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38A | 38 | A | en | A. Army | <div class="problem-statement"><div class="header"><div class="title">A. Army</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="788f4d7dda2c52f53a489cb7f5fdc088"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*800"] | https://codeforces.com/blog/entry/812 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4596eee11d2885b90c6642adbe10a57e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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38B | 38 | B | en | B. Chess | <div class="problem-statement"><div class="header"><div class="title">B. Chess</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b6e11aba1a2bc9db0cbb088c7d1b6ff7"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Implementation problems, programming technics, simulation", "Mathematics including integration, differential equations, etc"] | ["brute force", "implementation", "math", "*1200"] | https://codeforces.com/blog/entry/812 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4596eee11d2885b90c6642adbe10a57e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
38C | 38 | C | en | C. Blinds | <div class="problem-statement"><div class="header"><div class="title">C. Blinds</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5c11bbb359042577fd1f7658acdfba2f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force"] | ["brute force", "*1400"] | https://codeforces.com/blog/entry/812 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4596eee11d2885b90c6642adbe10a57e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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38D | 38 | D | en | D. Vasya the Architect | <div class="problem-statement"><div class="header"><div class="title">D. Vasya the Architect</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div c... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5e0ffabd8480fc8c9e0909b18bf0036c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1900"] | https://codeforces.com/blog/entry/812 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4596eee11d2885b90c6642adbe10a57e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
38E | 38 | E | en | E. Let's Go Rolling! | <div class="problem-statement"><div class="header"><div class="title">E. Let's Go Rolling!</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cla... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0bdd6d61415ede8169c4d31868ab7255"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Sortings, orderings"] | ["dp", "sortings", "*1800"] | https://codeforces.com/blog/entry/812 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4596eee11d2885b90c6642adbe10a57e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
38F | 38 | F | en | F. Smart Boy | <div class="problem-statement"><div class="header"><div class="title">F. Smart Boy</div><div class="time-limit"><div class="property-title">time limit per test</div>4 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6eca01d6b20ec3436e853cb8bcdaccfe"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Games, Sprague\u2013Grundy theorem", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["dp", "games", "strings", "*2100"] | https://codeforces.com/blog/entry/812 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4596eee11d2885b90c6642adbe10a57e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
38G | 38 | G | en | G. Queue | <div class="problem-statement"><div class="header"><div class="title">G. Queue</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7ea2d33abfeeaa97006f4cba96edb642"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc"] | ["data structures", "*2300"] | https://codeforces.com/blog/entry/812 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4596eee11d2885b90c6642adbe10a57e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
38H | 38 | H | en | H. The Great Marathon | <div class="problem-statement"><div class="header"><div class="title">H. The Great Marathon</div><div class="time-limit"><div class="property-title">time limit per test</div>4 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cl... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="abf9c7f40b2d0c250af52a17ed82edce"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming"] | ["dp", "*2400"] | https://codeforces.com/blog/entry/812 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="4596eee11d2885b90c6642adbe10a57e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
39A | 39 | A | en | A. C*++ Calculations | <div class="problem-statement"><div class="header"><div class="title">A. C*++ Calculations</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div clas... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2e7dab45407625c71e4f2a5123441d35"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Parsing expression grammar", "Greedy algorithms"] | ["expression parsing", "greedy", "*2000"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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39B | 39 | B | en | B. Company Income Growth | <div class="problem-statement"><div class="header"><div class="title">B. Company Income Growth</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div ... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="81fdfed4543ed4e2267bf406f41b0f76"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms"] | ["greedy", "*1300"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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39C | 39 | C | en | C. Moon Craters | <div class="problem-statement"><div class="header"><div class="title">C. Moon Craters</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="05b458296bc5e83140a221cac3a89d69"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Sortings, orderings"] | ["dp", "sortings", "*2100"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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39D | 39 | D | en | D. Cubical Planet | <div class="problem-statement"><div class="header"><div class="title">D. Cubical Planet</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="60f74c28b142411f8602776c4c4f3e40"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Mathematics including integration, differential equations, etc"] | ["math", "*1100"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
39E | 39 | E | en | E. What Has Dirichlet Got to Do with That? | <div class="problem-statement"><div class="header"><div class="title">E. What Has Dirichlet Got to Do with That?</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="3c5c4de8045eef31e395c19dcb1e1469"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Games, Sprague\u2013Grundy theorem"] | ["dp", "games", "*2000"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
39F | 39 | F | en | F. Pacifist frogs | <div class="problem-statement"><div class="header"><div class="title">F. Pacifist frogs</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f33290ae0834f18258e6322522fdabb9"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1300"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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39G | 39 | G | en | G. Inverse Function | <div class="problem-statement"><div class="header"><div class="title">G. Inverse Function</div><div class="time-limit"><div class="property-title">time limit per test</div>5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f634f2ec5d916ae5108a2a9714e0ba89"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*2400"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
39H | 39 | H | en | H. Multiplication Table | <div class="problem-statement"><div class="header"><div class="title">H. Multiplication Table</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div c... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="fc9d7791dcb29901adef2a68abd19abd"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1300"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
39I | 39 | I | en | I. Tram | <div class="problem-statement"><div class="header"><div class="title">I. Tram</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="property-t... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="d3180e0e9b3078c957490ee0ba708169"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | [] | ["*2500"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
39J | 39 | J | en | J. Spelling Check | <div class="problem-statement"><div class="header"><div class="title">J. Spelling Check</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="76a03b588fc4c6ef12c054daa46163e5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Hashing, hashtables", "Implementation problems, programming technics, simulation", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["hashing", "implementation", "strings", "*1500"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
39K | 39 | K | en | K. Testing | <div class="problem-statement"><div class="header"><div class="title">K. Testing</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>64 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1a3315146bceea273e2b88b5c0e02c85"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | [] | ["*2600"] | https://codeforces.com/blog/entry/786 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="2c951d740f6f5fd942ba000fa1c74679"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
40A | 40 | A | en | A. Find Color | <div class="problem-statement"><div class="header"><div class="title">A. Find Color</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pro... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a2a5daf2daffc0c837becb5949a146d5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Geometry, computational geometry", "Implementation problems, programming technics, simulation", "Mathematics including integration, differential equations, etc"] | ["constructive algorithms", "geometry", "implementation", "math", "*1300"] | https://codeforces.com/blog/entry/835 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a2448587f0b0309e076af46c2a86694c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
40B | 40 | B | en | B. Repaintings | <div class="problem-statement"><div class="header"><div class="title">B. Repaintings</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="53535a85bcce59fa60c7badbfdf07874"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Mathematics including integration, differential equations, etc"] | ["math", "*1600"] | https://codeforces.com/blog/entry/835 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a2448587f0b0309e076af46c2a86694c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
40C | 40 | C | en | C. Berland Square | <div class="problem-statement"><div class="header"><div class="title">C. Berland Square</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="adafaf99166e5bf90305477dcb92d3dc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation", "Mathematics including integration, differential equations, etc"] | ["implementation", "math", "*2300"] | https://codeforces.com/blog/entry/835 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a2448587f0b0309e076af46c2a86694c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
40D | 40 | D | en | D. Interesting Sequence | <div class="problem-statement"><div class="header"><div class="title">D. Interesting Sequence</div><div class="time-limit"><div class="property-title">time limit per test</div>3 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div ... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ca67327cb5dd573c3362e78738f99905"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Mathematics including integration, differential equations, etc"] | ["math", "*2600"] | https://codeforces.com/blog/entry/835 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a2448587f0b0309e076af46c2a86694c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
40E | 40 | E | en | E. Number Table | <div class="problem-statement"><div class="header"><div class="title">E. Number Table</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>216 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a1155f6fe95b8b3adf5045d6a3d9f142"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Combinatorics"] | ["combinatorics", "*2500"] | https://codeforces.com/blog/entry/835 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a2448587f0b0309e076af46c2a86694c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
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