#include<stdio.h>
#include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<utility>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<functional>
#include<math.h>
#include<random>
#include <bitset>
#include <cassert>
#include <complex>
using namespace std;
#define N (1000000000+7)
//#define N 998244353
#define INF 1e16
typedef long long ll;
typedef pair<int,int> P;
const int inf = 1e8;



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