えでゅふぉバチャ ABCDの4完 Dashboard - Educational Codeforces Round 42 (Rated for Div. 2) - Codeforces 青diffバチャ 全完(3完)できたので2問増やした https://kenkoooo.com/atcoder/#/contest/show/a521b21c-3701-4b8b-b53a-227b2f706b5c ギリギリ間…