#include <iostream>
#include <numeric>
#include <algorithm>
#include <string>
#include <vector>
#include <cmath>
#include <queue>

#define rep(i, a) FOR(i, 0, a)
#define FOR(i, a, b) for(int i = a; i < b; ++i)

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