#include <iostream>
using namespace std;



typedef unsigned long long ull;
/* ここからが本編 */
int main(void)
{
   int i,j;
   ull h,w;
   ull n,k;
   bool yes = 0;
   cin >> h >> w >> n >> k;
   if(n == k) k = 0;
   if((h * w) % n == k) yes = 1;
   if(yes) cout << "YES" << endl;
   else cout << "NO" << endl;
   return 0;
}