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

namespace yukicoder
{
    class yc
    {
        static void Main()
        {
            string[] str = Console.ReadLine().Split();
            long H = long.Parse(str[0]);
            long W = long.Parse(str[1]);
            long N = long.Parse(str[2]);
            long K = long.Parse(str[3]);
            long T = H * W;

            if (K == N && T % N == 0)
                Console.WriteLine("YES");
            else if (T % N == K) 
                Console.WriteLine("YES");
            else 
                Console.WriteLine("NO");
        }
    }
}