#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 10;
int main() {
  long long n, t;
  cin >> n >> t;
  long long a[n];
  long long ans = 0;
  for (int i = 0; i < n; ++i) {
    scanf("%lld", &a[i]);
    if (i != n - 1)
      ans += a[i] + 1;
    else
      ans += a[i];
  }
  if (ans == t)
    puts("YES");
  else
    puts("NO");
  return 0;
}
