#include <iostream>
#include <sstream>
#include <math.h>
#include <stack>
#include <set>
#include <algorithm>
#include <string>
#include <queue>
#include <stack>
#include <map>
#include <cstdio>
#include <vector>
using namespace std;

#define INF (1 << 30)
#define INFLL (1LL << 60)

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