#include <iostream>
using namespace std;

int main() {
  int n;
  double t, a, sum = 0;
  cin >> n >> a;
  for (int i = 0; i < n; i++) {
    cin >> t;
    sum += t;
  }
  double avg = sum / n;
  if (a == avg) cout << "YES" << endl;
  else cout << "NO" << endl;
}