package yukicoder166;
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();
		if(k==n)k=0;
		int mod=(h*w)%n;
		if(mod==k){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	}
}