#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>

#define ALL(x) (x).begin(),(x).end()
#define REP(i,n) for(int i = 0;i < (n);i++)
#define PI 3.14159265359
#define MOD 1000000007

using namespace std;

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