https://atcoder.jp/contests/abc289
https://atcoder.jp/contests/abc288/tasks/abc288_a
https://atcoder.jp/contests/abc289/tasks/abc289_b
共 2 条回复
https://atcoder.jp/contests/abc288/tasks/abc288_a
https://atcoder.jp/contests/abc289/tasks/abc289_b