https://www.acmicpc.net/problem/25556
https://www.acmicpc.net/problem/1021
https://www.acmicpc.net/problem/10818
https://www.acmicpc.net/problem/1158
https://www.acmicpc.net/problem/24174
https://www.acmicpc.net/problem/15552
https://www.acmicpc.net/problem/25304
https://www.acmicpc.net/problem/25314
https://www.acmicpc.net/problem/2830
https://www.acmicpc.net/problem/10828
https://www.acmicpc.net/problem/10845
https://www.acmicpc.net/problem/2167
https://www.acmicpc.net/problem/10812
https://www.acmicpc.net/problem/2563
https://www.acmicpc.net/problem/1543
https://www.acmicpc.net/problem/13223
https://www.acmicpc.net/problem/10158#😩