#include <bits/stdc++.h>
using namespace std;
int main(){
    int n,a; cin >> n >> a;
    int x[10];
    int sum;
    for(int i=0; i < n; i++){
        cin >> x[i];
        sum += x[i];
    }
    if(a == sum / n) cout << "YES" << endl;
    else cout << "NO" << endl;
    
}