Try the Chinese NOI contest type!

IMPORTANT: WHEN YOU REGISTER THIS CONTEST, IT WILL LET YOU FILL IN A VALUE, WHICH IS THE INVITATION CODE, PLEASE ENTER yc92.

This is NOT a contest made by Luogu officials, so the conteset does NOT provide English statements. Thank you for your understanding. You CAN use AI for translation. According to the Chinese NOI rules, the submissions will be judged AFTER THE CONTEST ENDS, it will end at 2026-09-30 21:00(UTC+8). We will give all the participants that using AI to help ssolve problems extra 10 points to mark them(The organizer's account—bcbgszyzh, is used by DeepSeek AI).

Welcome to rate this contest at https://codeforces.com/blog/entry/156295 .

I am very sorry for using these low-quality problems which bring a bad reputation to Chinese CPers and the Chinese NOI competition system.