i was solving this problem and after making few submissions i thought now it would pass, but i got wrong answer on test two,cause 256th number differs :(

here is my submission: https://codeforces.me/contest/1736/submission/218110763

it says out of bounds on long long. how could this happen with the given constraints.

what's more i can't see that test-case. so, i wanted ask whether someone can help me for this one.