#include <iostream>

using namespace std;

int main() {
    long long h,w,n,k;
    cin >> h >> w >> n >> k;
    long long p = (h * w) % n;
    if (p == 0) {
        if (k == n) cout << "YES" << endl;
        else cout << "NO" << endl;
    } else {
        if (k == p) cout << "YES" << endl;
        else cout << "NO" <<endl;
    }
    return 0;
}