#include <bits/stdc++.h>
using namespace std;

int main() {
    long long n, s;
    cin >> n >> s;
    vector<long long> a(n);
    for(long long &e : a) cin >> e;
    
    long long t = accumulate(a.begin(), a.end(), 0LL);
    cout << (n * s == t ? "YES" : "NO") << '\n';
    return 0;
}