import java.util.Scanner;


public class Main_yukicoder166 {

    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();

        if (h * w % n == k % n) {
        	System.out.println("YES");
        } else {
        	System.out.println("NO");
        }
        
        sc.close();
    }
}