#include <iostream>
using namespace std;
int main(){
    int n,x;
    double a,ans=0;
    cin >> n >> a;
    for(int i=0;i<n;i++){
        cin >> x;ans+=x;
    }ans/=n;
    if(ans==a)cout << "YES" << endl;
    else cout << "NO" << endl;
    return 0;
}