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

const ll mod = ll(1e9) + 7;
const int INF = 1<<29;

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