#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    long long n,a;
    cin >> n >> a;
    float ave = 0;
    for(int i = 1;i <= n;i++){
        int x;
        cin >> x;
        ave += x;
    }
    ave /= n;
    if(ave == a) cout << "YES" << endl;
    else cout << "NO" << endl;
    return 0;
}