import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long h = sc.nextLong();
		long w = sc.nextLong();
		long n = sc.nextLong();
		long k = sc.nextLong();

		long loser = h * w % n == 0 ? n : h * w % n;
		if(k == loser) System.out.println("YES");
		else  System.out.println("NO");
	}
}