#include <iostream>
using namespace std;


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