#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, k, t, t1 = 0;
  cin >> n >> k;
  cin >> t1;
  for (int i = 2; i <= n; i++) {
    cin >> t;
    t1 += t + 1;
  }
  if (t1 == k)
    cout << "YES";
  else
    cout << "NO";
}
