#include <bits/stdc++.h>

using namespace std;

int main() {
    double n, a;
    vector<long long> v;
    
    cin >> n >> a;
    
    long long tmp;
    for (int i = 0; i < n; i++) {
        cin >> tmp;
        v.push_back(tmp);
    }
    
    long long sum = accumulate(v.begin(), v.end(), 0LL);
    double avg = sum / n;
    
    if (avg == a) {
        cout << "YES" << endl;
    } else {
        cout << "NO" << endl;
    }
    
    return 0;
}