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

public class yukicoder
{
    public static int looser(int h, int w, int n)
    {
        int range = h * w;
        
        if(range % n == 0)
        {
            return n;
        }
        else
        {
            return range % n;
        }
    }
    
    public static void Main()
    {
        int[] input = Console.ReadLine().Trim().Split(' ').Select(x => int.Parse(x)).ToArray();
        int h = input[0];
        int w = input[1];
        int n = input[2];
        int k = input[3];

        if(looser(h, w, n) == k)
        {
            Console.WriteLine("YES");
        }
        else
        {
            Console.WriteLine("NO");
        }
    }
}