(in-package :cl-user)
(eval-when (:compile-toplevel :load-toplevel :execute)
  (sb-int:defconstant-eqx opt
    #+swank '(optimize (speed 3) (safety 2))
    #-swank '(optimize (speed 3) (safety 0) (debug 0))
    #'equal)
  #+swank (ql:quickload '(:cl-debug-print :fiveam :cp/util) :silent t)
  #+swank (use-package :cp/util :cl-user)
  #-swank (set-dispatch-macro-character
           #\# #\> (lambda (s c p) (declare (ignore c p)) `(values ,(read s nil nil t)))))
#+swank (set-dispatch-macro-character #\# #\> #'cl-debug-print:debug-print-reader)

(macrolet ((def (b)
             `(progn (deftype ,(intern (format nil "UINT~A" b)) () '(unsigned-byte ,b))
                     (deftype ,(intern (format nil "INT~A" b)) () '(signed-byte ,b))))
           (define-int-types (&rest bits) `(progn ,@(mapcar (lambda (b) `(def ,b)) bits))))
  (define-int-types 2 4 7 8 15 16 31 32 62 63 64))

(defconstant +mod+ 1000000007)

(defmacro dbg (&rest forms)
  #+swank (if (= (length forms) 1)
              `(format *error-output* "~A => ~A~%" ',(car forms) ,(car forms))
              `(format *error-output* "~A => ~A~%" ',forms `(,,@forms)))
  #-swank (declare (ignore forms)))

(declaim (inline println))
(defun println (obj &optional (stream *standard-output*))
  (let ((*read-default-float-format* 'double-float))
    (prog1 (princ obj stream) (terpri stream))))

;; BEGIN_INSERTED_CONTENTS
;;;
;;; Disjoint set (union by size & path compression)
;;;

(defpackage :cp/disjoint-set
  (:use :cl)
  (:export #:disjoint-set #:make-disjoint-set #:ds-data
           #:ds-root #:ds-unite! #:ds-connected-p #:ds-size))
(in-package :cp/disjoint-set)

(defstruct (disjoint-set
            (:constructor make-disjoint-set
                (size &aux (data (make-array size :element-type 'fixnum :initial-element -1))))
            (:conc-name ds-)
            (:predicate nil)
            (:copier nil))
  (data nil :type (simple-array fixnum (*))))

(declaim (inline ds-root))
(defun ds-root (disjoint-set x)
  "Returns the root of X."
  (declare ((mod #.array-total-size-limit) x))
  (let ((data (ds-data disjoint-set)))
    (labels ((recur (x)
               (if (< (aref data x) 0)
                   x
                   (setf (aref data x)
                         (recur (aref data x))))))
      (recur x))))

(declaim (inline ds-unite!))
(defun ds-unite! (disjoint-set x1 x2)
  "Destructively unites X1 and X2 and returns true iff X1 and X2 become
connected for the first time."
  (let ((root1 (ds-root disjoint-set x1))
        (root2 (ds-root disjoint-set x2)))
    (unless (= root1 root2)
      (let ((data (ds-data disjoint-set)))
        ;; NOTE: If you want X1 to always be root, just delete this form. (Time
        ;; complexity becomes worse, however.)
        (when (> (aref data root1) (aref data root2))
          (rotatef root1 root2))
        (incf (aref data root1) (aref data root2))
        (setf (aref data root2) root1)))))

(declaim (inline ds-connected-p))
(defun ds-connected-p (disjoint-set x1 x2)
  "Returns true iff X1 and X2 have the same root."
  (= (ds-root disjoint-set x1) (ds-root disjoint-set x2)))

(declaim (inline ds-size))
(defun ds-size (disjoint-set x)
  "Returns the size of the connected component to which X belongs."
  (- (aref (ds-data disjoint-set)
           (ds-root disjoint-set x))))

(defpackage :cp/read-fixnum
  (:use :cl)
  (:export #:read-fixnum))
(in-package :cp/read-fixnum)

(declaim (ftype (function * (values fixnum &optional)) read-fixnum))
(defun read-fixnum (&optional (in *standard-input*))
  "NOTE: cannot read -2^62"
  (macrolet ((%read-byte ()
               `(the (unsigned-byte 8)
                     #+swank (char-code (read-char in nil #\Nul))
                     #-swank (sb-impl::ansi-stream-read-byte in nil #.(char-code #\Nul) nil))))
    (let* ((minus nil)
           (result (loop (let ((byte (%read-byte)))
                           (cond ((<= 48 byte 57)
                                  (return (- byte 48)))
                                 ((zerop byte) ; #\Nul
                                  (error "Read EOF or #\Nul."))
                                 ((= byte #.(char-code #\-))
                                  (setq minus t)))))))
      (declare ((integer 0 #.most-positive-fixnum) result))
      (loop
        (let* ((byte (%read-byte)))
          (if (<= 48 byte 57)
              (setq result (+ (- byte 48)
                              (* 10 (the (integer 0 #.(floor most-positive-fixnum 10))
                                         result))))
              (return (if minus (- result) result))))))))

;; BEGIN_USE_PACKAGE
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/read-fixnum :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/disjoint-set :cl-user))
(in-package :cl-user)

;;;
;;; Body
;;;

(defun main ()
  (let* ((n (read))
         (m (read))
         (dset (make-disjoint-set n))
         (comp n))
    (dotimes (i m)
      (let ((a (- (read-fixnum) 1))
            (b (- (read-fixnum) 1)))
        (when (ds-unite! dset a b)
          (decf comp))))
    (println (- comp 1))))

#-swank (main)

;;;
;;; Test and benchmark
;;;

#+swank
(progn
  (defparameter *lisp-file-pathname* (uiop:current-lisp-file-pathname))
  (defparameter *dat-pathname* (uiop:merge-pathnames* "test.dat" *lisp-file-pathname*))
  (defparameter *problem-url* "https://atcoder.jp/contests/abl/tasks/abl_c"))

#+swank
(defun gen-dat ()
  (uiop:with-output-file (out *dat-pathname* :if-exists :supersede)
    (format out "")))

#+swank
(defun bench (&optional (out (make-broadcast-stream)))
  (time (run *dat-pathname* out)))

#-swank
(eval-when (:compile-toplevel)
  (when (or (> sb-c::*compiler-warning-count* 0)
            sb-c::*undefined-warnings*)
    (error "count: ~D, undefined warnings: ~A"
           sb-c::*compiler-warning-count*
           sb-c::*undefined-warnings*)))

;; To run: (5am:run! :sample)
#+swank
(5am:test :sample
  (5am:is
   (equal "1
"
          (run "3 1
1 2
" nil))))

Global OOD problem IDs are disjoint from train, validation, and in-distribution test problem IDs.

Score : 300 points

Problem Statement

There are N cities numbered 1 through N, and M bidirectional roads numbered 1 through M.
Road i connects City A_i and City B_i.

Snuke can perform the following operation zero or more times:

Choose two distinct cities that are not directly connected by a road, and build a new road between the two cities.

After he finishes the operations, it must be possible to travel from any city to any other cities by following roads (possibly multiple times).

What is the minimum number of roads he must build to achieve the goal?

Constraints

2 \leq N \leq 100,000

1 \leq M \leq 100,000

1 \leq A_i < B_i \leq N

No two roads connect the same pair of cities.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M
A_1 B_1
:
A_M B_M

Output

Print the answer.

Sample Input 1

3 1
1 2

Sample Output 1

1

Initially, there are three cities, and there is a road between City 1 and City 2.

Snuke can achieve the goal by building one new road, for example, between City 1 and City 3.
After that,

We can travel between 1 and 2 directly.

We can travel between 1 and 3 directly.

We can travel between 2 and 3 by following both roads (2 - 1 - 3).

Submitted source-code file size, in bytes.

Execution CPU time reported by official Project CodeNet metadata, in milliseconds.

Peak memory usage reported by official Project CodeNet metadata, in kilobytes.


(in-package :cl-user)
(eval-when (:compile-toplevel :load-toplevel :execute)
  (sb-int:defconstant-eqx opt
    #+swank '(optimize (speed 3) (safety 2))
    #-swank '(optimize (speed 3) (safety 0) (debug 0))
    #'equal)
  #+swank (ql:quickload '(:cl-debug-print :fiveam :cp/util) :silent t)
  #+swank (use-package :cp/util :cl-user)
  #-swank (set-dispatch-macro-character
           #\# #\> (lambda (s c p) (declare (ignore c p)) `(values ,(read s nil nil t)))))
#+swank (set-dispatch-macro-character #\# #\> #'cl-debug-print:debug-print-reader)

(macrolet ((def (b)
             `(progn (deftype ,(intern (format nil "UINT~A" b)) () '(unsigned-byte ,b))
                     (deftype ,(intern (format nil "INT~A" b)) () '(signed-byte ,b))))
           (define-int-types (&rest bits) `(progn ,@(mapcar (lambda (b) `(def ,b)) bits))))
  (define-int-types 2 4 7 8 15 16 31 32 62 63 64))

(defconstant +mod+ 998244353)

(defmacro dbg (&rest forms)
  #+swank (if (= (length forms) 1)
              `(format *error-output* "~A => ~A~%" ',(car forms) ,(car forms))
              `(format *error-output* "~A => ~A~%" ',forms `(,,@forms)))
  #-swank (declare (ignore forms)))

(declaim (inline println))
(defun println (obj &optional (stream *standard-output*))
  (let ((*read-default-float-format* 'double-float))
    (prog1 (princ obj stream) (terpri stream))))

;; BEGIN_INSERTED_CONTENTS

;; DEFINE-INTEGER-PACK and DEFINE-CONS-PACK are so to say poor man's variants of
;; DEFSTRUCT. Both "structures" can only have slots of fixed unsigned
;; bytes. DEFINE-INTEGER-PACK handles the concatenated slots as UNSIGNED-BYTE
;; and DEFINE-CONS-PACK handles them as (CONS (UNSIGNED-BYTE 62) (UNSIGNED-BYTE
;; 62)).

;; Example:
;; The following form defines the type NODE as (UNSIGNED-BYTE 9):
;; (define-integer-pack node (slot1 3) (slot2 5) (slot3 1))
;; This macro in addition defines relevant utilities: NODE-SLOT1, NODE-SLOT2,
;; NODE-SLOT3, setters and getters, PACK-NODE, the constructor, and
;; WITH-UNPACKING-NODE, the destructuring-bind-style macro.
;;
;; DEFINE-CONS-PACK is almost the same as DEFINE-INTEGER-PACK though it will be
;; suitable for the total bits in the range [63, 124].

(defpackage :cp/integer-pack
  (:use :cl)
  (:export #:define-integer-pack #:define-cons-pack))
(in-package :cp/integer-pack)

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defun %concat-name (&rest args)
    (if (cdr args)
        (format nil "~A-~A"
                (car args)
                (apply #'%concat-name (cdr args)))
        (car args)))

  (defun %concat+name+ (&rest args)
    (format nil "+~A+" (apply #'%concat-name args))))

(defmacro define-integer-pack (name &rest slot-descriptions)
  (assert slot-descriptions () "~A has no slots." name)
  (let* ((packer-name (intern (%concat-name "PACK" name)))
         (unpacker-macro-name (intern (%concat-name "WITH-UNPACKING" name)))
         (total-size 0)
         (slots (loop with position = 0
                      for (slot-name slot-size) in slot-descriptions
                      collect (progn (check-type slot-name symbol)
                                     (check-type slot-size (integer 1))
                                     (list slot-name slot-size position))
                      do (incf position slot-size)
                      finally (setq total-size position)))
         (revslots (reverse slots))
         (new-value (gensym "NEW-VALUE"))
         (tmp (gensym)))
    `(progn
       (deftype ,name () '(unsigned-byte ,total-size))
       ;; define most positive integer for every slot as constant
       ,@(loop for (slot-name slot-size _) in slots
               collect `(defconstant ,(intern (%concat+name+ "MAX" name slot-name))
                          (- (ash 1 ,slot-size) 1)))
       ;; setter and getter
       ,@(loop for (slot-name slot-size slot-position) in slots
               for accessor-name = (intern (%concat-name name slot-name))
               append `((declaim (inline ,accessor-name
                                         (setf ,accessor-name)))
                        (defun ,accessor-name (,name)
                          (declare (type ,name ,name))
                          (ldb (byte ,slot-size ,slot-position) ,name))
                        (defun (setf ,accessor-name) (,new-value ,name)
                          (declare (type ,name ,name))
                          (setf (ldb (byte ,slot-size ,slot-position) ,name) ,new-value))))
       ;; constructor
       (declaim (inline ,packer-name))
       (defun ,packer-name ,(loop for slot in slots collect (car slot))
         (declare ,@(loop for (slot-name slot-size _) in slots
                          collect `(type (unsigned-byte ,slot-size) ,slot-name )))
         (let ((,tmp ,(caar revslots)))
           (declare (type (unsigned-byte ,total-size) ,tmp))
           ,@(loop for (slot-name slot-size _) in (cdr revslots)
                   collect `(setq ,tmp (logxor ,slot-name
                                               (the (unsigned-byte ,total-size)
                                                    (ash ,tmp ,slot-size)))))
           ,tmp))
       ;; destructuring-bind-style macro
       (defmacro ,unpacker-macro-name (vars ,name &body body)
         (check-type vars list)
         (assert (= (length vars) ,(length slots)))
         `(let ((,',tmp ,,name))
            (declare (type (unsigned-byte ,,total-size) ,',tmp))
            (let* ,(loop for var in vars
                         for rest on ',slots
                         for (slot-name slot-size _) = (car rest)
                         collect `(,var
                                   (prog1 (the (unsigned-byte ,slot-size)
                                               (ldb (byte ,slot-size 0) ,',tmp))
                                     ,@(when (cdr rest)
                                         `((setq ,',tmp (ash ,',tmp ,(- slot-size))))))))
              ,@body))))))

(defmacro define-cons-pack (name &rest slot-descriptions)
  (assert slot-descriptions () "~A has no slots." name)
  (labels ((extract-62bit-slots (list)
             (let ((position 0))
               (loop for (slot-name slot-size) in list
                     while (<= (+ position slot-size) 62)
                     collect (list slot-name slot-size position)
                     do (incf position slot-size)))))
    (let* ((packer-name (intern (%concat-name "PACK" name)))
           (unpacker-macro-name (intern (%concat-name "WITH-UNPACKING" name)))
           (new-value (gensym "NEW-VALUE"))
           (tmp1 (gensym))
           (tmp2 (gensym))
           (tmp (gensym))
           (car-slots (extract-62bit-slots slot-descriptions))
           (car-revslots (reverse car-slots))
           (cdr-slots (extract-62bit-slots (nthcdr (length car-slots) slot-descriptions)))
           (cdr-revslots (reverse cdr-slots))
           (slots (append car-slots cdr-slots)))
      (assert (= (+ (length car-slots) (length cdr-slots))
                 (length slot-descriptions))
              () "Size restriction violated: each cell <= 62 bit, total size <= 124 bit")
      (unless (> (length cdr-slots) 0)
        (error "Whole size is too small. Use DEFINE-INTEGER-PACK instead."))
      (let ((car-width (+ (second (first car-revslots))
                          (third (first car-revslots))))
            (cdr-width (+ (second (first cdr-revslots))
                          (third (first cdr-revslots)))))
        `(progn
           (deftype ,name () '(cons (unsigned-byte ,car-width) (unsigned-byte ,cdr-width)))
           ;; define most positive integer for every slot as constant
           ,@(loop for (slot-name slot-size _) in slots
                   collect `(defconstant ,(intern (%concat+name+ "MAX" name slot-name))
                              (- (ash 1 ,slot-size) 1)))
           ;; setter and getter
           ,@(loop for slot in car-slots
                   for (slot-name slot-size slot-position) = slot
                   for accessor-name = (intern (%concat-name name slot-name))
                   append `((declaim (inline ,accessor-name (setf ,accessor-name)))
                            (defun ,accessor-name (,name)
                              (declare (type ,name ,name))
                              (ldb (byte ,slot-size ,slot-position)
                                   (the (unsigned-byte ,car-width) (car ,name))))
                            (defun (setf ,accessor-name) (,new-value ,name)
                              (declare (type ,name ,name))
                              (setf (ldb (byte ,slot-size ,slot-position)
                                         (the (unsigned-byte ,car-width) (car ,name)))
                                    ,new-value))))
           ,@(loop for slot in cdr-slots
                   for (slot-name slot-size slot-position) = slot
                   for accessor-name = (intern (%concat-name name slot-name))
                   append `((declaim (inline ,accessor-name (setf ,accessor-name)))
                            (defun ,accessor-name (,name)
                              (declare (type ,name ,name))
                              (ldb (byte ,slot-size ,slot-position)
                                   (the (unsigned-byte ,cdr-width) (cdr ,name))))
                            (defun (setf ,accessor-name) (,new-value ,name)
                              (declare (type ,name ,name))
                              (setf (ldb (byte ,slot-size ,slot-position)
                                         (the (unsigned-byte ,cdr-width) (cdr ,name)))
                                    ,new-value))))
           ;; constructor
           (declaim (inline ,packer-name))
           (defun ,packer-name ,(loop for slot in slots collect (car slot))
             (declare ,@(loop for (slot-name slot-size slot-position) in slots
                              collect `(type (unsigned-byte ,slot-size) ,slot-name)))
             (let ((,tmp1 ,(caar car-revslots))
                   (,tmp2 ,(caar cdr-revslots)))
               (declare (type (unsigned-byte ,car-width) ,tmp1)
                        (type (unsigned-byte ,cdr-width) ,tmp2))
               ,@(loop for (slot-name slot-size _) in (rest car-revslots)
                       collect `(setq ,tmp1 (logxor ,slot-name
                                                    (the (unsigned-byte ,car-width)
                                                         (ash ,tmp1 ,slot-size)))))
               ,@(loop for (slot-name slot-size _) in (rest cdr-revslots)
                       collect `(setq ,tmp2 (logxor ,slot-name
                                                    (the (unsigned-byte ,cdr-width)
                                                         (ash ,tmp2 ,slot-size)))))
               (cons ,tmp1 ,tmp2)))
           ;; destructuring-bind-style macro
           (defmacro ,unpacker-macro-name (vars ,name &body body)
             (check-type vars list)
             (assert (= (length vars) ,(length slots)))
             `(let* ((,',tmp ,,name)
                     (,',tmp1 (car ,',tmp))
                     (,',tmp2 (cdr ,',tmp)))
                (declare (type (unsigned-byte ,,car-width) ,',tmp1)
                         (type (unsigned-byte ,,cdr-width) ,',tmp2))
                (let* ,(loop for var in vars
                             for rest on ',car-slots
                             for (slot-name slot-size _) = (car rest)
                             collect `(,var
                                       (prog1 (the (unsigned-byte ,slot-size)
                                                   (ldb (byte ,slot-size 0) ,',tmp1))
                                         ,@(when (cdr rest)
                                             `((setq ,',tmp1 (ash ,',tmp1 ,(- slot-size))))))))
                  (let* ,(loop for var in (nthcdr ,(length car-slots) vars)
                               for rest on ',cdr-slots
                               for (slot-name slot-size _) = (car rest)
                               collect `(,var
                                         (prog1 (the (unsigned-byte ,slot-size)
                                                     (ldb (byte ,slot-size 0) ,',tmp2))
                                           ,@(when (cdr rest)
                                               `((setq ,',tmp2 (ash ,',tmp2 ,(- slot-size))))))))
                    ,@body)))))))))

(defpackage :cp/mod-power-table
  (:use :cl)
  (:export #:make-mod-power-table))
(in-package :cp/mod-power-table)

(declaim (inline make-mod-power-table))
(defun make-mod-power-table (base length modulus &optional (element-type '(unsigned-byte 31)))
  "Returns a vector of the given length: VECTOR[x] := BASE^x mod MODULUS."
  (declare (fixnum base)
           ((integer 0 #.most-positive-fixnum) length)
           ((integer 1 #.most-positive-fixnum) modulus))
  (let ((res (make-array length :element-type element-type)))
    (unless (zerop length)
      (setf (aref res 0) 1)
      (loop for i from 1 below length
            do (setf (aref res i)
                     (mod (* base (aref res (- i 1))) modulus))))
    res))

;;;
;;; Arithmetic operations with static modulus
;;;

(defpackage :cp/mod-operations
  (:use :cl)
  (:export #:define-mod-operations))
(in-package :cp/mod-operations)

;; NOTE: Currently MOD* and MOD+ doesn't apply MOD when the number of
;; parameters is one. For simplicity I won't fix it for now.
(defmacro define-mod-operations (divisor &optional (package (sb-int:sane-package)))
  (let ((mod* (intern "MOD*" package))
        (mod+ (intern "MOD+" package))
        (incfmod (intern "INCFMOD" package))
        (decfmod (intern "DECFMOD" package))
        (mulfmod (intern "MULFMOD" package)))
    `(progn
       (defun ,mod* (&rest args)
         (reduce (lambda (x y) (mod (* x y) ,divisor)) args))

       (defun ,mod+ (&rest args)
         (reduce (lambda (x y) (mod (+ x y) ,divisor)) args))

       #+sbcl
       (eval-when (:compile-toplevel :load-toplevel :execute)
         (locally (declare (sb-ext:muffle-conditions warning))
           (sb-c:define-source-transform ,mod* (&rest args)
             (if (null args)
                 1
                 (reduce (lambda (x y) `(mod (* ,x ,y) ,',divisor)) args)))
           (sb-c:define-source-transform ,mod+ (&rest args)
             (if (null args)
                 0
                 (reduce (lambda (x y) `(mod (+ ,x ,y) ,',divisor)) args)))))

       (define-modify-macro ,incfmod (delta)
         (lambda (x y) (mod (+ x y) ,divisor)))

       (define-modify-macro ,decfmod (delta)
         (lambda (x y) (mod (- x y) ,divisor)))

       (define-modify-macro ,mulfmod (multiplier)
         (lambda (x y) (mod (* x y) ,divisor))))))

(define-mod-operations cl-user::+mod+ :cl-user)

;;;
;;; Implicit treap
;;; (treap with implicit key)
;;;

;; TODO: abstraction

(defpackage :cp/implicit-treap
  (:use :cl :cp/mod-operations :cp/mod-power-table :cp/integer-pack)
  (:export #:itreap #:itreap-p #:itreap-count #:itreap-accumulator
           #:make-itreap #:invalid-itreap-index-error #:itreap-ref
           #:itreap-split #:itreap-merge #:itreap-insert #:itreap-delete
           #:itreap-push #:itreap-pop #:itreap-map #:do-itreap
           #:itreap-fold #:itreap-fold-bisect #:itreap-fold-bisect-from-end
           #:itreap-update #:itreap-reverse
           #:itreap-bisect-left #:itreap-bisect-right #:itreap-insort
           #:pack-node #:node-x))
(in-package :cp/implicit-treap)

;; Note:
;; - An empty treap is NIL.

(define-mod-operations cl-user::+mod+)

(declaim ((simple-array (unsigned-byte 31) (*)) *power10*))
(declaim ((simple-array (unsigned-byte 31) (* *)) *table*))
(sb-ext:define-load-time-global *power10*
  (make-mod-power-table 10 200001 cl-user::+mod+))
(sb-ext:define-load-time-global *table*
  (make-array '(10 200001) :element-type '(unsigned-byte 31) :initial-element 0))

(loop for d from 1 to 9
      do (loop for i from 1 to 200000
               do (setf (aref *table* d i)
                        (mod+ d (mod* (aref *table* d (- i 1)) 10)))))

(define-integer-pack node (x 31) (l 31))

(declaim (inline op))
(defun op (a b)
  "Is a binary operator comprising a monoid."
  (declare (node a b))
  (with-unpacking-node (x1 l1) a
    (with-unpacking-node (x2 l2) b
      (pack-node (mod+ (mod* x1 (aref *power10* l2))
                       x2)
                 (mod+ l1 l2)))))

(sb-int:defconstant-eqx +op-identity+ 0 #'equal
  "identity element w.r.t. OP")

(declaim (inline updater-op))
(defun updater-op (lazy x)
  "Is the operator to compute and update LAZY value. LAZY is the current LAZY
value and X is an operand."
  (if (zerop x)
      lazy
      x))

(defconstant +updater-identity+ 0
  "identity element w.r.t. UPDATER-OP")

(declaim (inline modifier-op))
(defun modifier-op (acc lazy size)
  "Is the operator to update ACCUMULATOR (and VALUE) based on LAZY value. ACC is
the current ACCUMULATOR value and LAZY is the LAZY value. SIZE is the length of
the target interval."
  (declare (ignorable size)
           (node acc))
  (if (zerop lazy)
      acc
      (let ((l (node-l acc)))
        (pack-node (aref *table* lazy l) l))))

(defstruct (itreap (:constructor %make-itreap (value priority &key left right (count 1) (accumulator value) (lazy +updater-identity+)))
                   (:copier nil)
                   (:conc-name %itreap-))
  (value +op-identity+ :type node)
  (accumulator +op-identity+ :type node)
  (lazy +updater-identity+ :type (unsigned-byte 8))
  (priority 0 :type (integer 0 #.most-positive-fixnum))
  (count 1 :type (mod #.most-positive-fixnum)) ; size of (sub)treap
  (left nil :type (or null itreap))
  (right nil :type (or null itreap)))

(declaim (inline itreap-count))
(defun itreap-count (itreap)
  "Returns the number of the elements of ITREAP."
  (declare ((or null itreap) itreap))
  (if itreap
      (%itreap-count itreap)
      0))

(declaim (inline itreap-accumulator))
(defun itreap-accumulator (itreap)
  "Returns the sum (w.r.t. OP) of the whole ITREAP:
ITREAP[0]+ITREAP[1]+...+ITREAP[SIZE-1]."
  (declare ((or null itreap) itreap))
  (if itreap
      (%itreap-accumulator itreap)
      +op-identity+))

(declaim (inline update-count))
(defun update-count (itreap)
  (declare (itreap itreap))
  (setf (%itreap-count itreap)
        (+ 1
           (itreap-count (%itreap-left itreap))
           (itreap-count (%itreap-right itreap)))))

(declaim (inline update-accumulator))
(defun update-accumulator (itreap)
  (declare (itreap itreap))
  (setf (%itreap-accumulator itreap)
        (if (%itreap-left itreap)
            (if (%itreap-right itreap)
                (let ((mid (op (%itreap-accumulator (%itreap-left itreap))
                               (%itreap-value itreap))))
                  (op mid (%itreap-accumulator (%itreap-right itreap))))
                (op (%itreap-accumulator (%itreap-left itreap))
                    (%itreap-value itreap)))
            (if (%itreap-right itreap)
                (op (%itreap-value itreap)
                    (%itreap-accumulator (%itreap-right itreap)))
                (%itreap-value itreap)))))

(declaim (inline force-up))
(defun force-up (itreap)
  "Propagates up the information from children."
  (declare (itreap itreap))
  (update-count itreap)
  (update-accumulator itreap))

(declaim (inline force-down))
(defun force-down (itreap)
  "Propagates down the information to children."
  (declare (itreap itreap))
  (unless (eql +updater-identity+ (%itreap-lazy itreap))
    (when (%itreap-left itreap)
      (setf (%itreap-lazy (%itreap-left itreap))
            (updater-op (%itreap-lazy (%itreap-left itreap))
                        (%itreap-lazy itreap)))
      (setf (%itreap-accumulator (%itreap-left itreap))
            (modifier-op (%itreap-accumulator (%itreap-left itreap))
                         (%itreap-lazy itreap)
                         (%itreap-count (%itreap-left itreap)))))
    (when (%itreap-right itreap)
      (setf (%itreap-lazy (%itreap-right itreap))
            (updater-op (%itreap-lazy (%itreap-right itreap))
                        (%itreap-lazy itreap)))
      (setf (%itreap-accumulator (%itreap-right itreap))
            (modifier-op (%itreap-accumulator (%itreap-right itreap))
                         (%itreap-lazy itreap)
                         (%itreap-count (%itreap-right itreap)))))
    (setf (%itreap-value itreap)
          (modifier-op (%itreap-value itreap)
                       (%itreap-lazy itreap)
                       1))
    (setf (%itreap-lazy itreap) +updater-identity+)))

(defun %heapify (node)
  "Makes it max-heap w.r.t. priorities by swapping the priorities of the whole
treap."
  (declare (optimize (speed 3) (safety 0)))
  (when node
    (let ((high-priority-node node))
      (when (and (%itreap-left node)
                 (> (%itreap-priority (%itreap-left node))
                    (%itreap-priority high-priority-node)))
        (setq high-priority-node (%itreap-left node)))
      (when (and (%itreap-right node)
                 (> (%itreap-priority (%itreap-right node))
                    (%itreap-priority high-priority-node)))
        (setq high-priority-node (%itreap-right node)))
      (unless (eql high-priority-node node)
        (rotatef (%itreap-priority high-priority-node)
                 (%itreap-priority node))
        (%heapify high-priority-node)))))

(declaim (inline make-itreap))
(defun make-itreap (size &key initial-element)
  (labels ((build (l r)
             (declare ((integer 0 #.most-positive-fixnum) l r))
             (if (= l r)
                 nil
                 (let* ((mid (ash (+ l r) -1))
                        (node (%make-itreap (or initial-element
                                                +op-identity+)
                                            (random most-positive-fixnum))))
                   (setf (%itreap-left node) (build l mid))
                   (setf (%itreap-right node) (build (+ mid 1) r))
                   (%heapify node)
                   (force-up node)
                   node))))
    (build 0 size)))

(define-condition invalid-itreap-index-error (type-error)
  ((itreap :initarg :itreap :reader invalid-itreap-index-error-itreap)
   (index :initarg :index :reader invalid-itreap-index-error-index))
  (:report
   (lambda (condition stream)
     (let ((index (invalid-itreap-index-error-index condition)))
       (if (consp index)
           (format stream "Invalid range [~W, ~W) for itreap ~W."
                   (car index)
                   (cdr index)
                   (invalid-itreap-index-error-itreap condition))
           (format stream "Invalid index ~W for itreap ~W."
                   index
                   (invalid-itreap-index-error-itreap condition)))))))

(defun itreap-split (itreap index)
  "Destructively splits ITREAP at INDEX and returns two treaps (in ascending
order)."
  (declare (optimize (speed 3))
           ((integer 0 #.most-positive-fixnum) index))
  (unless (<= index (itreap-count itreap))
    (error 'invalid-itreap-index-error :index index :itreap itreap))
  (labels ((recur (itreap ikey)
             (unless itreap
               (return-from itreap-split (values nil nil)))
             (force-down itreap)
             (let ((left-count (itreap-count (%itreap-left itreap))))
               (if (<= ikey left-count)
                   (multiple-value-bind (left right)
                       (itreap-split (%itreap-left itreap) ikey)
                     (setf (%itreap-left itreap) right)
                     (force-up itreap)
                     (values left itreap))
                   (multiple-value-bind (left right)
                       (itreap-split (%itreap-right itreap) (- ikey left-count 1))
                     (setf (%itreap-right itreap) left)
                     (force-up itreap)
                     (values itreap right))))))
    (recur itreap index)))

(defun itreap-merge (left right)
  "Destructively concatenates two ITREAPs. Note that this `merge' is different
from CL:MERGE and rather close to CL:CONCATENATE."
  (declare (optimize (speed 3))
           ((or null itreap) left right))
  (cond ((null left) (when right (force-down right) (force-up right)) right)
        ((null right) (when left (force-down left) (force-up left)) left)
        (t (force-down left)
           (force-down right)
           (if (> (%itreap-priority left) (%itreap-priority right))
               (progn
                 (setf (%itreap-right left)
                       (itreap-merge (%itreap-right left) right))
                 (force-up left)
                 left)
               (progn
                 (setf (%itreap-left right)
                       (itreap-merge left (%itreap-left right)))
                 (force-up right)
                 right)))))

(defun itreap-insert (itreap index obj)
  "Destructively inserts OBJ into ITREAP at INDEX and returns the resultant treap.

You cannot rely on the side effect. Use the returned value."
  (declare (optimize (speed 3))
           ((or null itreap) itreap)
           ((integer 0 #.most-positive-fixnum) index))
  (unless (<= index (itreap-count itreap))
    (error 'invalid-itreap-index-error :itreap itreap :index index))
  (let ((node (%make-itreap obj (random most-positive-fixnum))))
    (labels ((recur (itreap ikey)
               (declare ((integer 0 #.most-positive-fixnum) ikey))
               (unless itreap (return-from recur node))
               (force-down itreap)
               (if (> (%itreap-priority node) (%itreap-priority itreap))
                   (progn
                     (setf (values (%itreap-left node) (%itreap-right node))
                           (itreap-split itreap ikey))
                     (force-up node)
                     node)
                   (let ((left-count (itreap-count (%itreap-left itreap))))
                     (if (<= ikey left-count)
                         (setf (%itreap-left itreap)
                               (recur (%itreap-left itreap) ikey))
                         (setf (%itreap-right itreap)
                               (recur (%itreap-right itreap) (- ikey left-count 1))))
                     (force-up itreap)
                     itreap))))
      (recur itreap index))))

(defun itreap-delete (itreap index)
  "Destructively deletes the object at INDEX in ITREAP.

You cannot rely on the side effect. Use the returned value."
  (declare (optimize (speed 3))
           ((integer 0 #.most-positive-fixnum) index))
  (unless (< index (itreap-count itreap))
    (error 'invalid-itreap-index-error :itreap itreap :index index))
  (labels ((recur (itreap ikey)
             (declare ((integer 0 #.most-positive-fixnum) ikey))
             (force-down itreap)
             (let ((left-count (itreap-count (%itreap-left itreap))))
               (cond ((< ikey left-count)
                      (setf (%itreap-left itreap)
                            (recur (%itreap-left itreap) ikey))
                      (force-up itreap)
                      itreap)
                     ((> ikey left-count)
                      (setf (%itreap-right itreap)
                            (recur (%itreap-right itreap) (- ikey left-count 1)))
                      (force-up itreap)
                      itreap)
                     (t
                      (itreap-merge (%itreap-left itreap) (%itreap-right itreap)))))))
    (recur itreap index)))

(defmacro itreap-push (obj itreap pos)
  "Pushes OBJ to ITREAP at POS."
  `(setf ,itreap (itreap-insert ,itreap ,pos ,obj)))

(defmacro itreap-pop (itreap pos)
  "Returns the object at POS and deletes it."
  (let ((p (gensym)))
    `(let ((,p ,pos))
       (prog1 (itreap-ref ,itreap ,p)
         (setf ,itreap (itreap-delete ,itreap ,p))))))

(declaim (inline itreap-map))
(defun itreap-map (function itreap)
  "Successively applies FUNCTION to ITREAP[0], ..., ITREAP[SIZE-1]."
  (declare (function function))
  (labels ((recur (node)
             (when node
               (force-down node)
               (recur (%itreap-left node))
               (funcall function (%itreap-value node))
               (recur (%itreap-right node))
               (force-up node))))
    (recur itreap)))

(defmethod print-object ((object itreap) stream)
  (print-unreadable-object (object stream :type t)
    (let ((init t))
      (itreap-map (lambda (x)
                    (if init
                        (setq init nil)
                        (write-char #\  stream))
                    (write x :stream stream))
                  object))))

(defmacro do-itreap ((var itreap &optional result) &body body)
  "Successively binds ITREAP[0], ..., ITREAP[SIZE-1] to VAR and executes BODY
each time."
  `(block nil
     (itreap-map (lambda (,var) ,@body) ,itreap)
     ,result))

(defun itreap (&rest args)
  ;; NOTE: This function takes O(nlog(n)) time. Use MAKE-ITREAP for efficiency.
  (labels ((recur (list position itreap)
             (declare ((integer 0 #.most-positive-fixnum) position))
             (if (null list)
                 itreap
                 (recur (cdr list)
                        (1+ position)
                        (itreap-insert itreap position (car list))))))
    (recur args 0 nil)))

(declaim (inline itreap-ref))
(defun itreap-ref (itreap index)
  "Returns the element ITREAP[INDEX]."
  (declare ((integer 0 #.most-positive-fixnum) index))
  (unless (< index (itreap-count itreap))
    (error 'invalid-itreap-index-error :itreap itreap :index index))
  (labels ((%ref (itreap index)
             (declare ((integer 0 #.most-positive-fixnum) index))
             (force-down itreap)
             (prog1
                 (let ((left-count (itreap-count (%itreap-left itreap))))
                   (cond ((< index left-count)
                          (%ref (%itreap-left itreap) index))
                         ((> index left-count)
                          (%ref (%itreap-right itreap) (- index left-count 1)))
                         (t (%itreap-value itreap))))
               (force-up itreap))))
    (%ref itreap index)))

(declaim (inline (setf itreap-ref)))
(defun (setf itreap-ref) (new-value itreap index)
  "Sets ITREAP[INDEX] to the given value."
  (declare ((integer 0 #.most-positive-fixnum) index))
  (unless (< index (itreap-count itreap))
    (error 'invalid-itreap-index-error :itreap itreap :index index))
  (labels ((%set (itreap index)
             (declare ((integer 0 #.most-positive-fixnum) index))
             (force-down itreap)
             (prog1
                 (let ((left-count (itreap-count (%itreap-left itreap))))
                   (cond ((< index left-count)
                          (%set (%itreap-left itreap) index))
                         ((> index left-count)
                          (%set (%itreap-right itreap) (- index left-count 1)))
                         (t (setf (%itreap-value itreap) new-value))))
               (force-up itreap))))
    (%set itreap index)
    new-value))

(declaim (inline itreap-fold))
(defun itreap-fold (itreap l r)
  "Returns the `sum' (w.r.t. OP) of the range ITREAP[L, R)."
  (declare ((integer 0 #.most-positive-fixnum) l r))
  (unless (<= l r (itreap-count itreap))
    (error 'invalid-itreap-index-error :itreap itreap :index (cons l r)))
  (labels
      ((recur (itreap l r)
         (declare ((integer 0 #.most-positive-fixnum) l r))
         (unless itreap
           (return-from recur +op-identity+))
         (force-down itreap)
         (prog1
             (if (and (zerop l) (= r (%itreap-count itreap)))
                 (itreap-accumulator itreap)
                 (let ((left-count (itreap-count (%itreap-left itreap))))
                   (if (<= l left-count)
                       (if (< left-count r)
                           ;; LEFT-COUNT is in [L, R)
                           (op (op (recur (%itreap-left itreap) l (min r left-count))
                                   (%itreap-value itreap))
                               (recur (%itreap-right itreap) 0 (- r left-count 1)))
                           ;; LEFT-COUNT is in [R, END)
                           (recur (%itreap-left itreap) l (min r left-count)))
                       ;; LEFT-COUNT is in [0, L)
                       (recur (%itreap-right itreap) (- l left-count 1) (- r left-count 1)))))
           (force-up itreap))))
    (recur itreap l r)))

;; FIXME: might be problematic when two priorities collide and START is not
;; zero. (It will be negligible from the viewpoint of probability, however.)
(declaim (inline itreap-fold-bisect))
(defun itreap-fold-bisect (itreap test &optional (start 0))
  "Returns the largest index that satisfies (FUNCALL TEST (OP ITREAP[START]
ITREAP[START+1] ... ITREAP[index-1])).

Note:
- (FUNCALL TEST +OP-IDENTITY+) must be true.
- TEST must be monotone in the target range.
"
  (declare ((integer 0 #.most-positive-fixnum) start))
  (assert (funcall test +op-identity+))
  (multiple-value-bind (itreap-prefix itreap)
      (if (zerop start)
          (values nil itreap)
          (itreap-split itreap start))
    (labels
        ((recur (itreap offset prev-sum)
           (declare ((integer 0 #.most-positive-fixnum) offset)
                    #+sbcl (values (integer 0 #.most-positive-fixnum)))
           (unless itreap
             (return-from recur offset))
           (force-down itreap)
           (let ((sum prev-sum))
             (prog1
                 (cond ((not (funcall test (setq sum (op sum (itreap-accumulator (%itreap-left itreap))))))
                        (recur (%itreap-left itreap) offset prev-sum))
                       ((not (funcall test (setq sum (op sum (%itreap-value itreap)))))
                        (+ offset (itreap-count (%itreap-left itreap))))
                       (t
                        (recur (%itreap-right itreap)
                               (+ offset (itreap-count (%itreap-left itreap)) 1)
                               sum)))
               (force-up itreap)))))
      (prog1 (+ start (recur itreap 0 +op-identity+))
        (itreap-merge itreap-prefix itreap)))))

(declaim (inline itreap-fold-bisect-from-end))
(defun itreap-fold-bisect-from-end (itreap test &optional end)
  "Returns the smallest index that satisfies (FUNCALL TEST (OP ITREAP[index]
  ITREAP[index+1] ... ITREAP[END-1])).

Note:
- (FUNCALL TEST +OP-IDENTITY+) must be true.
- TEST must be monotone in the target range.
"
  (declare ((or null (integer 0 #.most-positive-fixnum)) end))
  (assert (funcall test +op-identity+))
  (multiple-value-bind (itreap itreap-suffix)
      (if end
          (itreap-split itreap end)
          (values itreap nil))
    (labels
        ((recur (itreap offset prev-sum)
           (declare ((integer 0 #.most-positive-fixnum) offset)
                    #+sbcl (values (integer 0 #.most-positive-fixnum)))
           (unless itreap
             (return-from recur offset))
           (force-down itreap)
           (let ((sum prev-sum))
             (prog1
                 (cond ((not (funcall test (setq sum (op (itreap-accumulator (%itreap-right itreap)) sum))))
                        (recur (%itreap-right itreap) offset prev-sum))
                       ((not (funcall test (setq sum (op (%itreap-value itreap) sum))))
                        (+ offset (itreap-count (%itreap-right itreap))))
                       (t
                        (recur (%itreap-left itreap)
                               (+ offset (itreap-count (%itreap-right itreap)) 1)
                               sum)))
               (force-up itreap)))))
      (prog1 (- (or end (itreap-count itreap))
                (recur itreap 0 +op-identity+))
        (itreap-merge itreap itreap-suffix)))))

(declaim (inline itreap-update))
(defun itreap-update (itreap operand l r)
  "Updates ITRAP by ITREAP[i] := (OP ITREAP[i] OPERAND) for all i in [l, r)"
  (declare ((integer 0 #.most-positive-fixnum) l r))
  (unless (<= l r (itreap-count itreap))
    (error 'invalid-itreap-index-error :itreap itreap :index (cons l r)))
  (labels
      ((recur (itreap l r)
         (declare ((integer 0 #.most-positive-fixnum) l r))
         (when itreap
           (if (and (zerop l) (= r (%itreap-count itreap)))
               (progn
                 (setf (%itreap-lazy itreap)
                       (updater-op (%itreap-lazy itreap) operand))
                 (force-down itreap))
               (let ((left-count (itreap-count (%itreap-left itreap))))
                 (force-down itreap)
                 (if (<= l left-count)
                     (if (< left-count r)
                         ;; LEFT-COUNT is in [L, R)
                         (progn
                           (recur (%itreap-left itreap) l (min r left-count))
                           (setf (%itreap-value itreap)
                                 (modifier-op (%itreap-value itreap) operand 1))
                           (recur (%itreap-right itreap) 0 (- r left-count 1)))
                         ;; LEFT-COUNT is in [R, END)
                         (recur (%itreap-left itreap) l (min r left-count)))
                     ;; LEFT-COUNT is in [0, L)
                     (recur (%itreap-right itreap) (- l left-count 1) (- r left-count 1)))))
           (force-up itreap))))
    (recur itreap l r)
    itreap))

;;;
;;; Below are utilities for treap whose values are sorted w.r.t. some order
;;;

(declaim (inline itreap-bisect-left)
         (ftype (function * (values (integer 0 #.most-positive-fixnum) &optional)) itreap-bisect-left))
(defun itreap-bisect-left (itreap value order)
  "Takes a **sorted** treap and returns the smallest index that satisfies
ITREAP[index] >= VALUE, where >= is the complement of ORDER. In other words,
this function returns a leftmost index at which value can be inserted with
keeping the order. Returns the size of ITREAP if ITREAP[length-1] <
VALUE. The time complexity is O(log(n))."
  (labels ((recur (count itreap)
             (declare ((integer 0 #.most-positive-fixnum) count))
             (cond ((null itreap) nil)
                   ((funcall order (%itreap-value itreap) value)
                    (recur count (%itreap-right itreap)))
                   (t
                    (let ((left-count (- count (itreap-count (%itreap-right itreap)) 1)))
                      (or (recur left-count (%itreap-left itreap))
                          left-count))))))
    (or (recur (itreap-count itreap) itreap)
        (itreap-count itreap))))

(declaim (inline itreap-bisect-right)
         (ftype (function * (values (integer 0 #.most-positive-fixnum) &optional)) itreap-bisect-right))
(defun itreap-bisect-right (itreap value order)
  "Takes a **sorted** treap and returns the smallest index that satisfies
VALUE < ITREAP[index], where < is ORDER. In other words, this function
returns a rightmost index at which VALUE can be inserted with keeping the
order. Returns the size of ITREAP if ITREAP[length-1] <= VALUE. The time
complexity is O(log(n))."
  (labels ((recur (count itreap)
             (declare ((integer 0 #.most-positive-fixnum) count))
             (cond ((null itreap) nil)
                   ((funcall order value (%itreap-value itreap))
                    (let ((left-count (- count (itreap-count (%itreap-right itreap)) 1)))
                      (or (recur left-count (%itreap-left itreap))
                          left-count)))
                   (t
                    (recur count (%itreap-right itreap))))))
    (or (recur (itreap-count itreap) itreap)
        (itreap-count itreap))))

(declaim (inline itreap-insort))
(defun itreap-insort (itreap obj order)
  "Does insertion to the sorted treap with keeping the order. You cannot rely on
the side effect. Use the returned value."
  (let ((pos (itreap-bisect-left itreap obj order)))
    (itreap-insert itreap pos obj)))

(defpackage :cp/read-fixnum
  (:use :cl)
  (:export #:read-fixnum))
(in-package :cp/read-fixnum)

(declaim (ftype (function * (values fixnum &optional)) read-fixnum))
(defun read-fixnum (&optional (in *standard-input*))
  "NOTE: cannot read -2^62"
  (macrolet ((%read-byte ()
               `(the (unsigned-byte 8)
                     #+swank (char-code (read-char in nil #\Nul))
                     #-swank (sb-impl::ansi-stream-read-byte in nil #.(char-code #\Nul) nil))))
    (let* ((minus nil)
           (result (loop (let ((byte (%read-byte)))
                           (cond ((<= 48 byte 57)
                                  (return (- byte 48)))
                                 ((zerop byte) ; #\Nul
                                  (error "Read EOF or #\Nul."))
                                 ((= byte #.(char-code #\-))
                                  (setq minus t)))))))
      (declare ((integer 0 #.most-positive-fixnum) result))
      (loop
        (let* ((byte (%read-byte)))
          (if (<= 48 byte 57)
              (setq result (+ (- byte 48)
                              (* 10 (the (integer 0 #.(floor most-positive-fixnum 10))
                                         result))))
              (return (if minus (- result) result))))))))

;; BEGIN_USE_PACKAGE
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/integer-pack :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/read-fixnum :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/mod-power-table :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/implicit-treap :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/mod-operations :cl-user))
(in-package :cl-user)

;;;
;;; Body
;;;

(defun main ()
  (declare #.cl-user::opt)
  (let* ((n (read))
         (q (read))
         (itreap (make-itreap n :initial-element (pack-node 1 1))))
    (declare (uint31 n q))
    (write-string
     (with-output-to-string (*standard-output* nil :element-type 'base-char)
       (dotimes (_ q)
         (let ((l (- (read-fixnum) 1))
               (r (read-fixnum))
               (d (read-fixnum)))
           (setq itreap (itreap-update itreap d l r))
           (println (node-x (itreap-accumulator itreap)))))))))

#-swank (main)

;;;
;;; Test and benchmark
;;;

#+swank
(progn
  (defparameter *lisp-file-pathname* (uiop:current-lisp-file-pathname))
  (defparameter *dat-pathname* (uiop:merge-pathnames* "test.dat" *lisp-file-pathname*))
  (defparameter *problem-url* "https://atcoder.jp/contests/abl/tasks/abl_e"))

#+swank
(defun gen-dat ()
  (uiop:with-output-file (out *dat-pathname* :if-exists :supersede)
    (format out "")))

#+swank
(defun bench (&optional (out (make-broadcast-stream)))
  (time (run *dat-pathname* out)))

#-swank
(eval-when (:compile-toplevel)
  (when (or (> sb-c::*compiler-warning-count* 0)
            sb-c::*undefined-warnings*)
    (error "count: ~D, undefined warnings: ~A"
           sb-c::*compiler-warning-count*
           sb-c::*undefined-warnings*)))

;; To run: (5am:run! :sample)
#+swank
(5am:test :sample
  (5am:is
   (equal "11222211
77772211
77333333
72333333
72311333
"
          (run "8 5
3 6 2
1 4 7
3 8 3
2 2 2
4 5 1
" nil)))
  (5am:is
   (equal "641437905
"
          (run "200000 1
123 456 7
" nil))))

Score : 500 points

Problem Statement

You have a string S of length N.
Initially, all characters in S are 1s.

You will perform queries Q times.
In the i-th query, you are given two integers L_i, R_i and a character D_i (which is a digit).
Then, you must replace all characters from the L_i-th to the R_i-th (inclusive) with D_i.

After each query, read the string S as a decimal integer, and print its value modulo 998,244,353.

Constraints

1 \leq N, Q \leq 200,000

1 \leq L_i \leq R_i \leq N

1 \leq D_i \leq 9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N Q
L_1 R_1 D_1
:
L_Q R_Q D_Q

Output

Print Q lines.
In the i-th line print the value of S after the i-th query, modulo 998,244,353.

Sample Input 1

8 5
3 6 2
1 4 7
3 8 3
2 2 2
4 5 1

Sample Output 1

11222211
77772211
77333333
72333333
72311333

Sample Input 2

200000 1
123 456 7

Sample Output 2

641437905

Don't forget to take the modulo.


(in-package :cl-user)
(eval-when (:compile-toplevel :load-toplevel :execute)
  (sb-int:defconstant-eqx opt
    #+swank '(optimize (speed 3) (safety 2))
    #-swank '(optimize (speed 3) (safety 0) (debug 0))
    #'equal)
  #+swank (ql:quickload '(:cl-debug-print :fiveam :cp/util) :silent t)
  #+swank (use-package :cp/util :cl-user)
  #-swank (set-dispatch-macro-character
           #\# #\> (lambda (s c p) (declare (ignore c p)) `(values ,(read s nil nil t)))))
#+swank (set-dispatch-macro-character #\# #\> #'cl-debug-print:debug-print-reader)

(macrolet ((def (b)
             `(progn (deftype ,(intern (format nil "UINT~A" b)) () '(unsigned-byte ,b))
                     (deftype ,(intern (format nil "INT~A" b)) () '(signed-byte ,b))))
           (define-int-types (&rest bits) `(progn ,@(mapcar (lambda (b) `(def ,b)) bits))))
  (define-int-types 2 4 7 8 15 16 31 32 62 63 64))

(defconstant +mod+ 998244353)

(defmacro dbg (&rest forms)
  #+swank (if (= (length forms) 1)
              `(format *error-output* "~A => ~A~%" ',(car forms) ,(car forms))
              `(format *error-output* "~A => ~A~%" ',forms `(,,@forms)))
  #-swank (declare (ignore forms)))

(declaim (inline println))
(defun println (obj &optional (stream *standard-output*))
  (let ((*read-default-float-format* 'double-float))
    (prog1 (princ obj stream) (terpri stream))))

;; BEGIN_INSERTED_CONTENTS
;;;
;;; Arithmetic operations with static modulus
;;;

(defpackage :cp/mod-operations
  (:use :cl)
  (:export #:define-mod-operations))
(in-package :cp/mod-operations)

;; NOTE: Currently MOD* and MOD+ doesn't apply MOD when the number of
;; parameters is one. For simplicity I won't fix it for now.
(defmacro define-mod-operations (divisor &optional (package (sb-int:sane-package)))
  (let ((mod* (intern "MOD*" package))
        (mod+ (intern "MOD+" package))
        (incfmod (intern "INCFMOD" package))
        (decfmod (intern "DECFMOD" package))
        (mulfmod (intern "MULFMOD" package)))
    `(progn
       (defun ,mod* (&rest args)
         (reduce (lambda (x y) (mod (* x y) ,divisor)) args))

       (defun ,mod+ (&rest args)
         (reduce (lambda (x y) (mod (+ x y) ,divisor)) args))

       #+sbcl
       (eval-when (:compile-toplevel :load-toplevel :execute)
         (locally (declare (sb-ext:muffle-conditions warning))
           (sb-c:define-source-transform ,mod* (&rest args)
             (if (null args)
                 1
                 (reduce (lambda (x y) `(mod (* ,x ,y) ,',divisor)) args)))
           (sb-c:define-source-transform ,mod+ (&rest args)
             (if (null args)
                 0
                 (reduce (lambda (x y) `(mod (+ ,x ,y) ,',divisor)) args)))))

       (define-modify-macro ,incfmod (delta)
         (lambda (x y) (mod (+ x y) ,divisor)))

       (define-modify-macro ,decfmod (delta)
         (lambda (x y) (mod (- x y) ,divisor)))

       (define-modify-macro ,mulfmod (multiplier)
         (lambda (x y) (mod (* x y) ,divisor))))))

(define-mod-operations cl-user::+mod+ :cl-user)

;;;
;;; Binomial coefficient with mod
;;; build: O(n)
;;; query: O(1)
;;;

(defpackage :cp/binomial-coefficient-mod
  (:use :cl)
  (:export #:binom #:perm #:multinomial #:stirling2 #:catalan #:+binom-mod+
           #:*fact* #:*fact-inv* #:*inv*))
(in-package :cp/binomial-coefficient-mod)

;; TODO: non-global handling

(defconstant +binom-size+ 510000)
(defconstant +binom-mod+ (if (boundp 'cl-user::+mod+)
                             (symbol-value 'cl-user::+mod+)
                             #.(+ (expt 10 9) 7)))

(sb-ext:define-load-time-global *fact*
  (make-array +binom-size+ :element-type '(unsigned-byte 31))
  "table of factorials")
(sb-ext:define-load-time-global *fact-inv*
  (make-array +binom-size+ :element-type '(unsigned-byte 31))
  "table of inverses of factorials")
(sb-ext:define-load-time-global *inv*
  (make-array +binom-size+ :element-type '(unsigned-byte 31))
  "table of inverses of non-negative integers")
(declaim ((simple-array (unsigned-byte 31) (*)) *fact* *fact-inv* *inv*))

(defun initialize-binom ()
  (declare (optimize (speed 3) (safety 0)))
  (setf (aref *fact* 0) 1
        (aref *fact* 1) 1
        (aref *fact-inv* 0) 1
        (aref *fact-inv* 1) 1
        (aref *inv* 1) 1)
  (loop for i from 2 below +binom-size+
        do (setf (aref *fact* i) (mod (* i (aref *fact* (- i 1))) +binom-mod+)
                 (aref *inv* i) (- +binom-mod+
                                   (mod (* (aref *inv* (rem +binom-mod+ i))
                                           (floor +binom-mod+ i))
                                        +binom-mod+))
                 (aref *fact-inv* i) (mod (* (aref *inv* i)
                                             (aref *fact-inv* (- i 1)))
                                          +binom-mod+))))

(initialize-binom)

(declaim (inline binom))
(defun binom (n k)
  "Returns nCk."
  (if (or (< n k) (< n 0) (< k 0))
      0
      (mod (* (aref *fact* n)
              (mod (* (aref *fact-inv* k) (aref *fact-inv* (- n k))) +binom-mod+))
           +binom-mod+)))

(declaim (inline perm))
(defun perm (n k)
  "Returns nPk."
  (if (or (< n k) (< n 0) (< k 0))
      0
      (mod (* (aref *fact* n) (aref *fact-inv* (- n k))) +binom-mod+)))

;; TODO: compiler macro or source-transform
(declaim (inline multinomial))
(defun multinomial (&rest ks)
  "Returns the multinomial coefficient K!/k_1!k_2!...k_n! for K = k_1 + k_2 +
... + k_n. K must be equal to or smaller than
MOST-POSITIVE-FIXNUM. (multinomial) returns 1."
  (let ((sum 0)
        (result 1))
    (declare ((integer 0 #.most-positive-fixnum) result sum))
    (dolist (k ks)
      (incf sum k)
      (setq result
            (mod (* result (aref *fact-inv* k)) +binom-mod+)))
    (mod (* result (aref *fact* sum)) +binom-mod+)))

(declaim (inline stirling2))
(defun stirling2 (n k)
  "Returns the stirling number of the second kind S2(n, k). Time complexity is
O(klog(n))."
  (declare ((integer 0 #.most-positive-fixnum) n k))
  (labels ((mod-power (base exp)
             (declare ((integer 0 #.most-positive-fixnum) base exp))
             (loop with res of-type (integer 0 #.most-positive-fixnum) = 1
                   while (> exp 0)
                   when (oddp exp)
                   do (setq res (mod (* res base) +binom-mod+))
                   do (setq base (mod (* base base) +binom-mod+)
                            exp (ash exp -1))
                   finally (return res))))
    (loop with result of-type fixnum = 0
          for i from 0 to k
          for delta = (mod (* (binom k i) (mod-power i n)) +binom-mod+)
          when (evenp (- k i))
          do (incf result delta)
             (when (>= result +binom-mod+)
               (decf result +binom-mod+))
          else
          do (decf result delta)
             (when (< result 0)
               (incf result +binom-mod+))
          finally (return (mod (* result (aref *fact-inv* k)) +binom-mod+)))))

(declaim (inline catalan))
(defun catalan (n)
  "Returns the N-th Catalan number."
  (declare ((integer 0 #.most-positive-fixnum) n))
  (mod (* (aref *fact* (* 2 n))
          (mod (* (aref *fact-inv* (+ n 1))
                  (aref *fact-inv* n))
               +binom-mod+))
       +binom-mod+))

;;;
;;; Fast Number Theoretic Transform
;;; Reference:
;;; https://github.com/ei1333/library/blob/master/math/fft/number-theoretic-transform-friendly-mod-int.cpp
;;; https://github.com/atcoder/ac-library/tree/master/atcoder
;;;

(defpackage :cp/ntt
  (:use :cl)
  (:export #:define-ntt #:check-ntt-vector #:ntt-int #:ntt-vector #:+ntt-mod+))
(in-package :cp/ntt)

(deftype ntt-int () '(unsigned-byte 31))
(deftype ntt-vector () '(simple-array ntt-int (*)))

(eval-when (:compile-toplevel :load-toplevel :execute)
  (declaim (inline %tzcount))
  (defun %tzcount (x)
    "Returns the number of trailing zero bits. Note that (%TZCOUNT 0) = -1."
    (- (integer-length (logand x (- x))) 1))
  (defun %mod-power (base exp modulus)
    (declare (ntt-int base exp modulus))
    (let ((res 1))
      (declare (ntt-int res))
      (loop while (> exp 0)
            when (oddp exp)
            do (setq res (mod (* res base) modulus))
            do (setq base (mod (* base base) modulus)
                     exp (ash exp -1)))
      res))
  (defun %mod-inverse (x modulus)
    (%mod-power x (- modulus 2) modulus))
  (defun %calc-generator (modulus)
    "MODULUS must be prime."
    (declare (ntt-int modulus))
    (assert (>= modulus 2))
    (case modulus
      (2 1)
      (167772161 3)
      (469762049 3)
      (754974721 11)
      (998244353 3)
      (otherwise
       (let ((divs (make-array 20 :element-type 'ntt-int :initial-element 0))
             (count 1)
             (x (floor (- modulus 1) 2)))
         (declare ((integer 0 #.most-positive-fixnum) x))
         (setf (aref divs 0) 2)
         (loop while (evenp x)
               do (setq x (floor x 2)))
         (loop for i of-type ntt-int from 3 by 2
               while (<= (* i i) x)
               when (zerop (mod x i))
               do (setf (aref divs count) i)
                  (incf count)
                  (loop while (zerop (mod x i))
                        do (setq x (floor x i))))
         (when (> x 1)
           (setf (aref divs count) x)
           (incf count))
         (loop for g of-type ntt-int from 2
               for ok = t
               do (dotimes (i count)
                    (when (= 1 (%mod-power g (floor (- modulus 1) (aref divs i)) modulus))
                      (setq ok nil)
                      (return)))
               when ok
               do (return g)))))))

;; KLUDGE: This function depends on SBCL's behaviour. Actually ADJUST-ARRAY
;; isn't guaranteed to preserve the given VECTOR.
(declaim (ftype (function * (values ntt-vector &optional)) %adjust-array))
(defun %adjust-array (vector length)
  (declare (vector vector))
  (let ((vector (coerce vector 'ntt-vector)))
    (if (= (length vector) length)
        (copy-seq vector)
        (adjust-array vector length :initial-element 0))))

(defun check-ntt-vector (vector)
  (declare (optimize (speed 3))
           (vector vector))
  (let ((len (length vector)))
    (assert (zerop (logand len (- len 1)))) ;; power of two
    (check-type len ntt-int)))

(defmacro define-ntt (modulus &key ntt inverse-ntt convolve mod-inverse mod-power)
  (let* ((ntt (or ntt (intern "NTT!")))
         (inverse-ntt (or inverse-ntt (intern "INVERSE-NTT!")))
         (convolve (or convolve (intern "CONVOLVE")))
         (mod-power (or mod-power (gensym "MOD-POWER")))
         (mod-inverse (or mod-inverse (gensym "MOD-INVERSE")))
         (ntt-base (gensym "*NTT-BASE*"))
         (ntt-inv-base (gensym "*NTT-INV-BASE*"))
         (base-size (%tzcount (- modulus 1)))
         (root (%calc-generator modulus)))
    (assert (typep modulus 'ntt-int))
    `(progn
       (declaim (inline ,mod-power))
       (defun ,mod-power (base exp)
         (declare (ntt-int base)
                  ((integer 0 #.most-positive-fixnum) exp))
         (let ((res 1))
           (declare (ntt-int res))
           (loop while (> exp 0)
                 when (oddp exp)
                 do (setq res (mod (* res base) ,modulus))
                 do (setq base (mod (* base base) ,modulus)
                          exp (ash exp -1)))
           res))
       (declaim (inline ,mod-inverse))
       (defun ,mod-inverse (x)
         (,mod-power x (- ,modulus 2)))
       (declaim (ntt-vector ,ntt-base ,ntt-inv-base))
       (sb-ext:define-load-time-global ,ntt-base
         (make-array ,base-size :element-type 'ntt-int))
       (sb-ext:define-load-time-global ,ntt-inv-base
         (make-array ,base-size :element-type 'ntt-int))
       (dotimes (i ,base-size)
         (setf (aref ,ntt-base i)
               (mod (- (%mod-power ,root (ash (- ,modulus 1) (- (+ i 2))) ,modulus))
                    ,modulus)
               (aref ,ntt-inv-base i)
               (%mod-inverse (aref ,ntt-base i) ,modulus)))

       (declaim (ftype (function * (values ntt-vector &optional)) ,ntt))
       (defun ,ntt (vector)
         (declare (optimize (speed 3) (safety 0))
                  (vector vector))
         (check-ntt-vector vector)
         (labels ((mod* (x y) (mod (* x y) ,modulus))
                  (mod+ (x y)
                    (let ((res (+ x y)))
                      (if (>= res ,modulus)
                          (- res ,modulus)
                          res)))
                  (mod- (x y) (mod+ x (- ,modulus y))))
           (declare (inline mod* mod+ mod-))
           (let* ((vector (coerce vector 'ntt-vector))
                  (len (length vector))
                  (base ,ntt-base))
             (declare (ntt-vector vector base)
                      (ntt-int len))
             (when (<= len 1)
               (return-from ,ntt vector))
             (loop for m of-type ntt-int = (ash len -1) then (ash m -1)
                   while (> m 0)
                   for w of-type ntt-int = 1
                   for k of-type ntt-int = 0
                   do (loop for s of-type ntt-int from 0 below len by (* 2 m)
                            do (loop for i from s below (+ s m)
                                     for j from (+ s m)
                                     for x = (aref vector i)
                                     for y = (mod* (aref vector j) w)
                                     do (setf (aref vector i) (mod+ x y)
                                              (aref vector j) (mod- x y)))
                               (incf k)
                               (setq w (mod* w (aref base (%tzcount k))))))
             vector)))

       (declaim (ftype (function * (values ntt-vector &optional)) ,inverse-ntt))
       (defun ,inverse-ntt (vector &optional inverse)
         (declare (optimize (speed 3) (safety 0))
                  (vector vector))
         (check-ntt-vector vector)
         (labels ((mod* (x y)
                    (declare (ntt-int x y))
                    (mod (* x y) ,modulus))
                  (mod+ (x y)
                    (declare (ntt-int x y))
                    (let ((res (+ x y)))
                      (if (>= res ,modulus)
                          (- res ,modulus)
                          res)))
                  (mod- (x y)
                    (declare (ntt-int x y))
                    (mod+ x (- ,modulus y))))
           (declare (inline mod* mod+ mod-))
           (let* ((vector (coerce vector 'ntt-vector))
                  (len (length vector))
                  (base ,ntt-inv-base))
             (declare (ntt-vector vector base)
                      (ntt-int len))
             (when (<= len 1)
               (return-from ,inverse-ntt vector))
             (loop for m of-type ntt-int = 1 then (ash m 1)
                   while (< m len)
                   for w of-type ntt-int = 1
                   for k of-type ntt-int = 0
                   do (loop for s of-type ntt-int from 0 below len by (* 2 m)
                            do (loop for i from s below (+ s m)
                                     for j from (+ s m)
                                     for x = (aref vector i)
                                     for y = (aref vector j)
                                     do (setf (aref vector i) (mod+ x y)
                                              (aref vector j) (mod* (mod- x y) w)))
                               (incf k)
                               (setq w (mod* w (aref base (%tzcount k))))))
             (when inverse
               (let ((inv-len (,mod-power len (- ,modulus 2))))
                 (dotimes (i len)
                   (setf (aref vector i) (mod* inv-len (aref vector i))))))
             vector)))

       (declaim (ftype (function * (values ntt-vector &optional)) ,convolve))
       (defun ,convolve (vector1 vector2)
         (declare (optimize (speed 3))
                  (vector vector1 vector2))
         (let ((len1 (length vector1))
               (len2 (length vector2)))
           (when (or (zerop len1) (zerop len2))
             (return-from ,convolve (make-array 0 :element-type 'ntt-int)))
           (let* ((mul-len (max 0 (- (+ len1 len2) 1)))
                  ;; power of two ceiling
                  (required-len (ash 1 (integer-length (max 0 (- mul-len 1)))))
                  (vector1 (,ntt (%adjust-array vector1 required-len)))
                  (vector2 (,ntt (%adjust-array vector2 required-len))))
             (declare ((mod #.array-total-size-limit) mul-len))
             (dotimes (i required-len)
               (setf (aref vector1 i)
                     (mod (* (aref vector1 i) (aref vector2 i)) ,modulus)))
             (adjust-array (,inverse-ntt vector1 t) mul-len)))))))

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defconstant +ntt-mod+ 998244353))

#+(or)
(define-ntt #.+ntt-mod+)

(defpackage :cp/read-fixnum
  (:use :cl)
  (:export #:read-fixnum))
(in-package :cp/read-fixnum)

(declaim (ftype (function * (values fixnum &optional)) read-fixnum))
(defun read-fixnum (&optional (in *standard-input*))
  "NOTE: cannot read -2^62"
  (macrolet ((%read-byte ()
               `(the (unsigned-byte 8)
                     #+swank (char-code (read-char in nil #\Nul))
                     #-swank (sb-impl::ansi-stream-read-byte in nil #.(char-code #\Nul) nil))))
    (let* ((minus nil)
           (result (loop (let ((byte (%read-byte)))
                           (cond ((<= 48 byte 57)
                                  (return (- byte 48)))
                                 ((zerop byte) ; #\Nul
                                  (error "Read EOF or #\Nul."))
                                 ((= byte #.(char-code #\-))
                                  (setq minus t)))))))
      (declare ((integer 0 #.most-positive-fixnum) result))
      (loop
        (let* ((byte (%read-byte)))
          (if (<= 48 byte 57)
              (setq result (+ (- byte 48)
                              (* 10 (the (integer 0 #.(floor most-positive-fixnum 10))
                                         result))))
              (return (if minus (- result) result))))))))

(defpackage :cp/polynomial-ntt
  (:use :cl :cp/ntt)
  (:export #:poly-multiply #:poly-inverse #:poly-floor #:poly-mod #:poly-sub #:poly-add
           #:multipoint-eval #:poly-total-prod))
(in-package :cp/polynomial-ntt)

(define-ntt #.+ntt-mod+
  :convolve poly-multiply
  :mod-inverse %mod-inverse)

(declaim (ftype (function * (values ntt-vector &optional)) poly-inverse))
(defun poly-inverse (poly &optional result-length)
  (declare (optimize (speed 3))
           (vector poly)
           ((or null fixnum) result-length))
  (let* ((poly (coerce poly 'ntt-vector))
         (n (length poly)))
    (declare (ntt-vector poly))
    (when (or (zerop n)
              (zerop (aref poly 0)))
      (error 'division-by-zero
             :operation #'poly-inverse
             :operands poly))
    (let ((res (make-array 1
                           :element-type 'ntt-int
                           :initial-element (%mod-inverse (aref poly 0))))
          (result-length (or result-length n)))
      (declare (ntt-vector res))
      (loop for i of-type ntt-int = 1 then (ash i 1)
            while (< i result-length)
            for decr = (poly-multiply (poly-multiply res res)
                                      (subseq poly 0 (min (length poly) (* 2 i))))
            for decr-len = (length decr)
            do (setq res (adjust-array res (* 2 i) :initial-element 0))
               (dotimes (j (* 2 i))
                 (setf (aref res j)
                       (mod (the ntt-int
                                 (+ (mod (* 2 (aref res j)) +ntt-mod+)
                                    (if (>= j decr-len) 0 (- +ntt-mod+ (aref decr j)))))
                            +ntt-mod+))))
      (adjust-array res result-length))))

(declaim (ftype (function * (values ntt-vector &optional)) poly-floor))
(defun poly-floor (poly1 poly2)
  (declare (optimize (speed 3))
           (vector poly1 poly2))
  (let* ((poly1 (coerce poly1 'ntt-vector))
         (poly2 (coerce poly2 'ntt-vector))
         (deg1 (+ 1 (or (position 0 poly1 :from-end t :test-not #'eql) -1)))
         (deg2 (+ 1 (or (position 0 poly2 :from-end t :test-not #'eql) -1))))
    (when (> deg2 deg1)
      (return-from poly-floor (make-array 0 :element-type 'ntt-int)))
    (setq poly1 (nreverse (subseq poly1 0 deg1))
          poly2 (nreverse (subseq poly2 0 deg2)))
    (let* ((res-len (+ 1 (- deg1 deg2)))
           (res (adjust-array (poly-multiply poly1 (poly-inverse poly2 res-len))
                              res-len)))
      (nreverse res))))

(declaim (ftype (function * (values ntt-vector &optional)) poly-sub))
(defun poly-sub (poly1 poly2)
  (declare (optimize (speed 3))
           (vector poly1 poly2))
  (let* ((poly1 (coerce poly1 'ntt-vector))
         (poly2 (coerce poly2 'ntt-vector))
         (len (max (length poly1) (length poly2)))
         (res (make-array len :element-type 'ntt-int :initial-element 0)))
    (replace res poly1)
    (dotimes (i (length poly2))
      (let ((value (+ (aref res i)
                      (the ntt-int (- +ntt-mod+ (aref poly2 i))))))
        (setf (aref res i)
              (if (>= value +ntt-mod+)
                  (- value +ntt-mod+)
                  value))))
    res))

(declaim (ftype (function * (values ntt-vector &optional)) poly-add))
(defun poly-add (poly1 poly2)
  (declare (optimize (speed 3))
           (vector poly1 poly2))
  (let* ((poly1 (coerce poly1 'ntt-vector))
         (poly2 (coerce poly2 'ntt-vector))
         (len (max (length poly1) (length poly2)))
         (res (make-array len :element-type 'ntt-int :initial-element 0)))
    (replace res poly1)
    (dotimes (i (length poly2))
      (let ((value (+ (aref res i) (aref poly2 i))))
        (setf (aref res i)
              (if (>= value +ntt-mod+)
                  (- value +ntt-mod+)
                  value))))
    res))

(declaim (ftype (function * (values ntt-vector &optional)) poly-mod))
(defun poly-mod (poly1 poly2)
  (declare (optimize (speed 3))
           (vector poly1 poly2))
  (let ((poly1 (coerce poly1 'ntt-vector))
        (poly2 (coerce poly2 'ntt-vector)))
    (when (loop for x across poly1 always (zerop x))
      (return-from poly-mod (make-array 0 :element-type 'ntt-int)))
    (let* ((res (poly-sub poly1 (poly-multiply (poly-floor poly1 poly2) poly2)))
           (end (+ 1 (or (position 0 res :from-end t :test-not #'eql) -1))))
      (subseq res 0 end))))

(declaim (ftype (function * (values ntt-vector &optional)) poly-total-prod))
(defun poly-total-prod (polys)
  "Returns the total polynomial product: polys[0] * polys[1] * ... * polys[n-1]."
  (declare (vector polys))
  (let* ((n (length polys))
         (dp (make-array n :element-type t)))
    (declare ((mod #.array-total-size-limit) n))
    (when (zerop n)
      (return-from poly-total-prod (make-array 1 :element-type 'ntt-int :initial-element 1)))
    (replace dp polys)
    (loop for width of-type (mod #.array-total-size-limit) = 1 then (ash width 1)
          while (< width n)
          do (loop for i of-type (mod #.array-total-size-limit) from 0 by (* width 2)
                   while (< (+ i width) n)
                   do (setf (aref dp i)
                            (poly-multiply (aref dp i) (aref dp (+ i width))))))
    (coerce (aref dp 0) 'ntt-vector)))

(declaim (ftype (function * (values ntt-vector &optional)) multipoint-eval))
(defun multipoint-eval (poly points)
  (declare (optimize (speed 3))
           (vector poly points)
           #+sbcl (sb-ext:muffle-conditions style-warning))
  (check-ntt-vector points)
  (let* ((poly (coerce poly 'ntt-vector))
         (points (coerce points 'ntt-vector))
         (len (length points))
         (table (make-array (max 0 (- (* 2 len) 1)) :element-type 'ntt-vector))
         (res (make-array len :element-type 'ntt-int)))
    (unless (zerop len)
      (sb-int:named-let %build ((l 0) (r len) (pos 0))
        (declare ((integer 0 #.most-positive-fixnum) l r pos))
        (if (= (- r l) 1)
            (let ((lin (make-array 2 :element-type 'ntt-int)))
              (setf (aref lin 0) (- +ntt-mod+ (aref points l)) ;; NOTE: non-zero
                    (aref lin 1) 1)
              (setf (aref table pos) lin))
            (let ((mid (ash (+ l r) -1)))
              (%build l mid (+ 1 (* pos 2)))
              (%build mid r (+ 2 (* pos 2)))
              (setf (aref table pos)
                    (poly-multiply (aref table (+ 1 (* pos 2)))
                                   (aref table (+ 2 (* pos 2))))))))
      (sb-int:named-let %eval ((poly poly) (l 0) (r len) (pos 0))
        (declare ((integer 0 #.most-positive-fixnum) l r pos))
        (if (= (- r l) 1)
            (let ((tmp (poly-mod poly (aref table pos))))
              (setf (aref res l) (if (zerop (length tmp)) 0 (aref tmp 0))))
            (let ((mid (ash (+ l r) -1)))
              (%eval (poly-mod poly (aref table (+ (* 2 pos) 1))) l mid (+ (* 2 pos) 1))
              (%eval (poly-mod poly (aref table (+ (* 2 pos) 2))) mid r (+ (* 2 pos) 2))))))
    res))

(defpackage :cp/mod-inverse
  (:use :cl)
  (:export #:mod-inverse))
(in-package :cp/mod-inverse)

;; TODO: signal DIVISION-BY-ZERO for non-coprime input when safety >= 1
(declaim (inline mod-inverse)
         (ftype (function * (values (mod #.most-positive-fixnum) &optional)) mod-inverse))
(defun mod-inverse (a modulus)
  "Solves ax ≡ 1 mod m. A and M must be coprime."
  (declare ((integer 1 #.most-positive-fixnum) modulus))
  (let ((a (mod a modulus))
        (b modulus)
        (u 1)
        (v 0))
    (declare (fixnum a b u v))
    (loop until (zerop b)
          for quot = (floor a b)
          do (decf a (the fixnum (* quot b)))
             (rotatef a b)
             (decf u (the fixnum (* quot v)))
             (rotatef u v))
    (mod u modulus)))

(defpackage :cp/mod-power-table
  (:use :cl)
  (:export #:make-mod-power-table))
(in-package :cp/mod-power-table)

(declaim (inline make-mod-power-table))
(defun make-mod-power-table (base length modulus &optional (element-type '(unsigned-byte 31)))
  "Returns a vector of the given length: VECTOR[x] := BASE^x mod MODULUS."
  (declare (fixnum base)
           ((integer 0 #.most-positive-fixnum) length)
           ((integer 1 #.most-positive-fixnum) modulus))
  (let ((res (make-array length :element-type element-type)))
    (unless (zerop length)
      (setf (aref res 0) 1)
      (loop for i from 1 below length
            do (setf (aref res i)
                     (mod (* base (aref res (- i 1))) modulus))))
    res))

;;;
;;; Binary heap
;;;

(defpackage :cp/abstract-heap
  (:use :cl)
  (:export #:heap-empty-error #:define-binary-heap))
(in-package :cp/abstract-heap)

(define-condition heap-empty-error (error)
  ((heap :initarg :heap :reader heap-empty-error-heap))
  (:report
   (lambda (condition stream)
     (format stream "Attempted to pop empty heap ~W" (heap-empty-error-heap condition)))))

(defmacro define-binary-heap (name &key order (element-type 'fixnum))
  "Defines a binary heap specialized for the given order and the element
type. This macro defines a structure of the given NAME and relevant functions:
MAKE-<NAME>, <NAME>-PUSH, <NAME>-POP, <NAME>-CLEAR, <NAME>-EMPTY-P,
<NAME>-COUNT, and <NAME>-PEEK.

If ORDER is not given, heap for dynamic order is defined instead: -PUSH and -POP
functions take order as an argument."
  (check-type name symbol)
  (let* ((string-name (string name))
         (fname-push (intern (format nil "~A-PUSH" string-name)))
         (fname-pop (intern (format nil "~A-POP" string-name)))
         (fname-clear (intern (format nil "~A-CLEAR" string-name)))
         (fname-empty-p (intern (format nil "~A-EMPTY-P" string-name)))
         (fname-count (intern (format nil "~A-COUNT" string-name)))
         (fname-peek (intern (format nil "~A-PEEK" string-name)))
         (fname-make (intern (format nil "MAKE-~A" string-name)))
         (acc-position (intern (format nil "~A-POSITION" string-name)))
         (acc-data (intern (format nil "~A-DATA" string-name)))
         (order (or order 'order)))
    `(progn
       (locally
           ;; prevent style warnings
           (declare #+sbcl (sb-ext:muffle-conditions style-warning))
         (defstruct (,name
                     (:constructor ,fname-make
                         (size
                          &aux
                          (data (make-array (1+ size)
                                            :element-type ',(if (eql element-type '*) t  element-type))))))
           (data nil :type (simple-array ,element-type (*)))
           (position 1 :type (integer 1 #.array-total-size-limit))))

       (declaim #+sbcl (sb-ext:maybe-inline ,fname-push))
       (defun ,fname-push (obj heap ,@(when (eql order 'order) '(order)))
         "Adds OBJ to HEAP."
         (declare (optimize (speed 3))
                  (type ,name heap))
         (symbol-macrolet ((position (,acc-position heap)))
           (when (>= position (length (,acc-data heap)))
             (setf (,acc-data heap)
                   (adjust-array (,acc-data heap)
                                 (min (- array-total-size-limit 1)
                                      (* position 2)))))
           (let ((data (,acc-data heap)))
             (declare ((simple-array ,element-type (*)) data))
             (labels ((heapify (pos)
                        (declare (optimize (speed 3) (safety 0)))
                        (unless (= pos 1)
                          (let ((parent-pos (ash pos -1)))
                            (when (funcall ,order (aref data pos) (aref data parent-pos))
                              (rotatef (aref data pos) (aref data parent-pos))
                              (heapify parent-pos))))))
               (setf (aref data position) obj)
               (heapify position)
               (incf position)
               heap))))

       (declaim #+sbcl (sb-ext:maybe-inline ,fname-pop))
       (defun ,fname-pop (heap ,@(when (eql order 'order) '(order)))
         "Removes and returns the element at the top of HEAP."
         (declare (optimize (speed 3))
                  (type ,name heap))
         (symbol-macrolet ((position (,acc-position heap)))
           (let ((data (,acc-data heap)))
             (declare ((simple-array ,element-type (*)) data))
             (labels ((heapify (pos)
                        (declare (optimize (speed 3) (safety 0))
                                 ((integer 1 #.array-total-size-limit) pos))
                        (let* ((child-pos1 (+ pos pos))
                               (child-pos2 (1+ child-pos1)))
                          (when (<= child-pos1 position)
                            (if (<= child-pos2 position)
                                (if (funcall ,order (aref data child-pos1) (aref data child-pos2))
                                    (unless (funcall ,order (aref data pos) (aref data child-pos1))
                                      (rotatef (aref data pos) (aref data child-pos1))
                                      (heapify child-pos1))
                                    (unless (funcall ,order (aref data pos) (aref data child-pos2))
                                      (rotatef (aref data pos) (aref data child-pos2))
                                      (heapify child-pos2)))
                                (unless (funcall ,order (aref data pos) (aref data child-pos1))
                                  (rotatef (aref data pos) (aref data child-pos1))))))))
               (when (= position 1)
                 (error 'heap-empty-error :heap heap))
               (prog1 (aref data 1)
                 (decf position)
                 (setf (aref data 1) (aref data position))
                 (heapify 1))))))

       (declaim (inline ,fname-clear))
       (defun ,fname-clear (heap)
         "Makes HEAP empty."
         (setf (,acc-position heap) 1)
         heap)

       (declaim (inline ,fname-empty-p))
       (defun ,fname-empty-p (heap)
         "Returns true iff HEAP is empty."
         (= 1 (,acc-position heap)))

       (declaim (inline ,fname-count))
       (defun ,fname-count (heap)
         "Returns the current number of the elements in HEAP."
         (- (,acc-position heap) 1))

       (declaim (inline ,fname-peek))
       (defun ,fname-peek (heap)
         "Returns the topmost element of HEAP. Signals HEAP-EMPTY-ERROR if HEAP
is empty."
         (if (= 1 (,acc-position heap))
             (error 'heap-empty-error :heap heap)
             (aref (,acc-data heap) 1))))))

#+(or)
(define-binary-heap heap
  :order #'>
  :element-type fixnum)

;; BEGIN_USE_PACKAGE
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/abstract-heap :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/mod-power-table :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/mod-inverse :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/polynomial-ntt :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/read-fixnum :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/ntt :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/binomial-coefficient-mod :cl-user))
(eval-when (:compile-toplevel :load-toplevel :execute)
  (use-package :cp/mod-operations :cl-user))
(in-package :cl-user)

;;;
;;; Body
;;;

(define-binary-heap heap
  :order (lambda (poly1 poly2)
           (< (length poly1) (length poly2)))
  :element-type ntt-vector)

(defun main ()
  (let* ((n (read))
         (hcounter (make-array 100000 :element-type 'uint31 :initial-element 0))
         (powers (make-mod-power-table 499122177 100001 +mod+))
         (fs (make-array (+ n 1) :element-type 'uint31 :initial-element 0)))
    (declare (uint31 n))
    (dotimes (i (* 2 n))
      (incf (aref hcounter (- (read-fixnum) 1))))
    (dotimes (i (+ n 1))
      (setf (aref fs i) (mod* (aref *fact* (* 2 i))
                              (aref powers i)
                              (aref *fact-inv* i))))
    (let* ((hcounter (delete 0 hcounter))
           (que (make-heap n)))
      (dotimes (j (length hcounter))
        (let* ((k (aref hcounter j))
               (poly (make-array (+ 1 (floor k 2)) :element-type 'uint31)))
          (loop for i from 0 below (length poly)
                do (setf (aref poly i)
                         (mod* (binom k (* 2 i)) (aref fs i))))
          (dbg k poly)
          (heap-push poly que)))
      (loop while (>= (heap-count que) 2)
            for poly1 = (heap-pop que)
            for poly2 = (heap-pop que)
            do (heap-push (poly-multiply poly1 poly2) que))
      (let ((poly (heap-pop que))
            (res 0))
        #>poly
        (loop for i from 0 below (length poly)
              for sign = 1 then (* sign -1)
              ;; while (<= (* 2 i) n)
              do (incfmod res (mod* (aref poly i) (aref fs (- n i)) sign)))
        (println res)))))

#-swank (main)

;;;
;;; Test and benchmark
;;;

#+swank
(progn
  (defparameter *lisp-file-pathname* (uiop:current-lisp-file-pathname))
  (defparameter *dat-pathname* (uiop:merge-pathnames* "test.dat" *lisp-file-pathname*))
  (defparameter *problem-url* "https://atcoder.jp/contests/abl/tasks/abl_f"))

#+swank
(defun gen-dat ()
  (uiop:with-output-file (out *dat-pathname* :if-exists :supersede)
    (format out "")))

#+swank
(defun bench (&optional (out (make-broadcast-stream)))
  (time (run *dat-pathname* out)))

#-swank
(eval-when (:compile-toplevel)
  (when (or (> sb-c::*compiler-warning-count* 0)
            sb-c::*undefined-warnings*)
    (error "count: ~D, undefined warnings: ~A"
           sb-c::*compiler-warning-count*
           sb-c::*undefined-warnings*)))

;; To run: (5am:run! :sample)
#+swank
(5am:test :sample
  (5am:is
   (equal "2
"
          (run "2
1
1
2
3
" nil)))
  (5am:is
   (equal "516
"
          (run "5
30
10
20
40
20
10
10
30
50
60
" nil))))

Score : 600 points

Problem Statement

There are 2N people numbered 1 through 2N.
The height of Person i is h_i.

How many ways are there to make N pairs of people such that the following conditions are satisfied?
Compute the answer modulo 998,244,353.

Each person is contained in exactly one pair.

For each pair, the heights of the two people in the pair are different.

Two ways are considered different if for some p and q, Person p and Person q are paired in one way and not in the other.

Constraints

1 \leq N \leq 50,000

1 \leq h_i \leq 100,000

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
h_1
:
h_{2N}

Output

Print the answer.

Sample Input 1

2
1
1
2
3

Sample Output 1

2

There are two ways:

Form the pair (Person 1, Person 3) and the pair (Person 2, Person 4).

Form the pair (Person 1, Person 4) and the pair (Person 2, Person 3).

Sample Input 2

5
30
10
20
40
20
10
10
30
50
60

Sample Output 2

516