/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner sc = new Scanner(System.in);
		
		final long H = sc.nextLong();
		final long W = sc.nextLong();
		final long N = sc.nextLong();
		final long K = sc.nextLong();
		
		System.out.println((H * W) % N == (K % N) ? "YES" : "NO");
	}
}