import java.util.Scanner;

public class Main{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		while(sc.hasNext()){
			long h=sc.nextLong();
			long w=sc.nextLong();
			long n=sc.nextLong();
			long k=sc.nextLong();
			if(((h*w)%n==0 ? n : (h*w)%n) == k) System.out.println("YES");
			else System.out.println("NO");
		}
	}
}