package yukicoder;

import java.util.Scanner;

public class Yuki166 {
	
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long h = scan.nextLong();
		long w = scan.nextLong();
		long n = scan.nextLong();
		long k = scan.nextLong();
		scan.close();
		
		long mas = (h * w) % n;
		// System.out.println(mas);

		if( mas - k == 0){
			System.out.println("YES");
		}else if( mas == 0 && n == k){ 
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}
	}	
}