#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <iostream>
#include <numeric>
#include <optional>
#include <vector>

using namespace std;

int main() {
    int64_t h, w, n, k;
    cin >> h >> w >> n >> k;
    cout << ((h * w) % n == k % n ? "YES" : "NO") << endl;
    return 0;
}