#include <bits/stdc++.h>
using namespace std;
using ull = unsigned long long;
ull H, W, N, K;
void input() { cin >> H >> W >> N >> K; }

void solve() { cout << ((H * W % N == K % N) ? "YES" : "NO") << endl; }

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  input();
  solve();
  getchar();
}