#include <bits/stdc++.h>

using namespace std;

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