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

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            long[] x = Console.ReadLine().Split().Select(long.Parse).ToArray();
            long a = x[0] % x[2];
            a *= x[1] % x[2];
            Console.WriteLine(a % x[2] == x[3] % x[2] ? "YES" : "NO");
        }
    }
}