#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
int main() {
  long long h,w,n,k;
  cin >> h >> w >> n >> k;
  if((h*w-k)%n==0) {
      cout << "YES" << endl;
  }
  else {
      cout << "NO" << endl;
  }
}