Codeforces 884 B. Japanese Crosswords Strike Back Problem Solution

http://codeforces.com/contest/884/problem/B

#include<bits/stdc++.h>

using namespace std;

int main()
{
    int m,n,sum=0,a,num;
     while (cin >> n >> m) {
        for (int i = 0; i < n; i++) {
            cin >> num;
            sum += num ;
        }
       
        if (sum +(n-1)== m) {
            cout << "YES" << endl;
        }
        else {
            cout << "NO" << endl;
        }
    }
    return 0;
}