#include <iostream>

using lint = long long;

void solve() {
    int n;
    lint s;
    std::cin >> n >> s;
    s *= n;

    while (n--) {
        lint x;
        std::cin >> x;
        s -= x;
    }

    std::cout << (s == 0 ? "YES" : "NO") << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}