import java.util.Scanner;

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

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