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

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