### PeterParker's blog

By PeterParker, history, 5 years ago,

I used the fact that each in each connected component there should be an edge between each pair of vertices. Hence the number of edges given should be equal to — summation x*(x-1)/2 for each connected component, where x = size of the connected component.

I used int and got a WA and when I replaced it with long long it got Accepted. Now my question is if the answer has to be "YES

" then sum should be <= 150000 (since that is the range of M in the question) so int should suffice then why did I get a WA?