#include <bits/stdc++.h>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;

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