#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <algorithm>
#include <sstream>
#include <map>
#include <set>
using namespace std;


#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
/* 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;
}