#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<vector>
#include<map>
#include<queue>
#include<string>
#include<sstream>
#include<cmath>
using namespace std;

int main(){

  long long int h, w, n, k;
  cin >> h >> w >> n >> k;

  if( (h*w)%n == k%n ) cout << "YES" << endl;
  else cout << "NO" << endl;

  return 0;
}