#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>

using namespace std;

int main() {
	long long h, w, n, k;

	cin >> h >> w >> n >> k;
	cout << ((h * w) % n == k % n ? "YES" : "NO") << endl;
	return 0;
}