#include<iostream>
#include<string>
#include<algorithm>
#include<cmath>
#include<iomanip>
#include<cstring>
#include<map>
#include<vector>
using namespace std;
typedef long long int ll;

int main(){

  ll H, W, N, K, square;
  cin >> H >> W >> N >> K;
  square=H*W;
  square%=N;
  K%=N;
  if(square==K){
    cout << "YES" << endl;
  } else {
    cout << "NO" << endl;
  }

  return 0;
}