In recent codeforces div 2 contest I got wa because of this in problem C — counting orders
I don's understand what is difference between two ,Aren't they both same ?
Here is my submission for which got wa
https://mirror.codeforces.com/contest/1828/submission/205934626
Here is same submission for which got ac by changing ans = ans* something
https://mirror.codeforces.com/contest/1828/submission/205934493