I was virtual participating Codeforces Round #831 (Div. 1 + Div. 2), but when I was solving problem D, I had some problems submitting my solution.

Here are some of my submissions on problem D which are completely same in logic, and all of them were denial of judgement.

Because I was virtual participating and not able to see the judgement results, I asked my friend to check what's wrong with it. Here is the submission: 178637017

Checker Log

g++.exe: fatal error: cannot execute 'C:/Programs/msys2-mingw64-9/bin/../lib/gcc/x86_64-w64-mingw32/9.2.0/../../../../x86_64-w64-mingw32/bin/as.exe': CreateProcess: No such file or directory

compilation terminated.

It seems that there is something wrong with checker. To confirm that, I submitted the solution of jiangly(which was accepted while real time contest)(178638115), and turned out to be the same result.

I think maybe it's a bug on Codeforces, or the checker in this problem has something wrong.