#include<bits/stdc++.h>
using namespace std;
#define ll long long 
#define pb push_back
#define fr first
#define sc second
typedef vector<int> Vi;
typedef pair<int,int> Pii;
typedef pair<int,Pii> Pip; 
const int INF = (1<<30);
const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};

int main()
{
  int h, w, n, k;
  cin >> h >> w >> n >> k;

  int tmp = h * w % n;
  if( tmp == 0 ) tmp = n;
  if( tmp == k ) cout << "YES" << endl;
  else cout << "NO" << endl;
}