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();
		int n = sc.nextInt();
		int k = sc.nextInt();

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