problem_set_id,start_at,end_at
1440507257074442240,2021-09-22 10:44:00,2022-09-21 11:02:00
1495575668283748352,,
1513173293052600320,,
1518117049115811840,2022-04-30 14:22:00,2022-04-30 16:32:00
1522752763463884800,,
1522765863088975872,2022-05-07 10:30:00,2022-05-07 11:30:00
1524551515375833088,2022-05-12 08:45:00,2022-05-14 20:30:00
1527082232005836800,2022-05-19 08:21:00,2022-05-23 10:21:00
1533423567629684736,,
1533434675035869184,2022-06-05 21:04:00,2022-06-19 23:04:00
1534720487757430784,2022-06-09 10:11:00,2022-07-06 16:38:00
1540676665888989184,2022-06-25 20:50:00,2022-06-25 21:00:00
1548887567511576576,2022-07-18 12:28:00,2022-07-18 14:28:00
1569493759262134272,2022-09-13 09:13:00,2022-09-14 11:13:00