Hello Codeforces,

I am wondering how to solve this problem here.

Any idea? Thankyou.

Hi Everyone.

Now I'm wondering about how to count (a*b) % c? 1 <= a,b,c <=10^18.

Any advice?

Thank you.

Hi Everyone.

Now I'm wondering about how many different ways of choosing K( K <= 1000 ; K <= N) numbers from 0 until N-1 such that the sum is divisible by N ( N <= 10^9).

Any advice?

Thank you.