#include <iostream>
#include <vector>
#include <queue>
using namespace std;

double sum(vector<int> d){
  double total = 0;
  for(int i = 0; i < d.size(); i++){
    total += d[i];
  }
  return total;
}

void solve() {
  int n,a;
  cin >> n >> a;
  vector<int> d(n);
  for(auto &x : d) cin >> x;
  double ave = sum(d) / n;
  cout << (ave == a ? "YES" : "NO") << endl;
}

int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);

  solve();

  return 0;
}