Hey there.

I was doing an A2OJ ladder, and I came across this problem (185C - Хитроумная жирная крыса), that nobody had managed to pass system tests during the contests for some odd reason. When I went to check the editorial, there was no explanation, only a smiley face, so I decided to check the submission list, but I was not able to understand the code.

It would help me very much if someone could help me understand how to solve the problem. Thanks in advance.