// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
int main() {
    // Input
    int n, a;
    cin >> n >> a;
    vector<int> x(n);
    rep(i, n) cin >> x[i];

    // Output
    double mean = accumulate(x.begin(), x.end(), 0.0) / n;
    cout << (a == mean ? "YES" : "NO") << endl;
}