#include <bits/stdc++.h>
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef pair<int, int> pii;
typedef long long ll;
typedef unsigned long long ull;
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define pb push_back
#define mp make_pair
#define loop(i,a,b) for(ull i=(a);i<ull(b);++i)
#define rep(i,n) loop(i,0,n)
#define iter(i,c) for(auto i=(c).begin(); i!=(c).end(); ++i)
#define riter(i,c) for(auto i=(c).rbegin(); i!=(c).rend(); ++i)
const double eps = 1e-10;
const double pi = acos(-1.0);
const double inf = (int)1e8;

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