In Codeforces Round 215 (Div. 1) 19790402 I got WA on test 79, However, I thought I got the correct answer when I used Custom Invocation.

What the problem is???

I passed this problem by replace %ld with %d, but I do want to know Why I get different answers between custom invocation and problem test?

By the way, I'm glad to know how to cause this WA, since I thought there is no different between %ld and %d in GNU G++11 5.10 :)