Hello, everyone! Codeforces Round #631 will be held at Apr/03/2020 17:35 (Moscow time).
The problems are almost from me(dreamoon_love_AA), except one problem of which the idea is from drazil and developed by me. Also we want to thank 300iq for helping me prepare the round, isaf27, tmt514, rowdark, yp155136, wangyenjen, n_dao107 and woruo27 for testing this round, and MikeMirzayanov for Codeforces and Polygon.
This is my third time organizing a problemset for a Codeforces round (my previous rounds: Codeforces Round #272, Codeforces Round #320).
Good luck and have fun!