#include <iostream>
using namespace std;

int main(){
    int n;
    float ans;
    cin >> n >> ans;
    int x;
    float sum = 0;
    for(int i = 0; i < n; i++){
        cin >> x;
        sum += x;
    }
    if((sum/n == ans)) cout << "YES" << endl;
    else cout << "NO" << endl;

    return 0;
}