using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        // No.166 マス埋めゲーム

        var hwnk = Console.ReadLine();
        int H = int.Parse(hwnk.Split(' ')[0]);
        int W = int.Parse(hwnk.Split(' ')[1]);
        int N = int.Parse(hwnk.Split(' ')[2]);
        int K = int.Parse(hwnk.Split(' ')[3]);

        Console.WriteLine(H * W % N == 0 ? (N == K ? "YES" : "NO") : ((H * W % N) == K ? "YES" : "NO"));
    }
}