using System;
using System.Linq;

class Program
{
    static void Main()
    {
        int[] i = Console.ReadLine().Split().Select(int.Parse).ToArray();
        int h = i[0];
        int w = i[1];
        int n = i[2];
        int k = i[3];

        int a = h * w;

        if (a % n == k || a % n == 0 && k == n) Console.WriteLine("YES");
        else Console.WriteLine("NO");
    }
}