#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <math.h>
#include <deque>
#include <queue>
using namespace std;
typedef long long int ll;
typedef unsigned long long int ull;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    ll h,w,n,k; cin >> h >> w >> n >> k;
    h=h*w%n;
    if(h==0)h=n;
    if(h!=k){
        printf("NO\n");
    }
    else{
        printf("YES\n");
    }
}