#include <iostream>

using lint = long long;

void solve() {
    lint h, w, n, k;
    std::cin >> h >> w >> n >> k;

    lint p = h * w % n;
    k %= n;
    std::cout << (p == k ? "YES" : "NO") << std::endl;
}

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

    solve();

    return 0;
}