#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<n;i++)
typedef pair<int,int>P;

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