package no167;

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int h = sc.nextInt();
		int w = sc.nextInt();
		long n = sc.nextLong();
		long k = sc.nextLong();
		if ((long) h * w % n == k % n) {
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	}
}