class MyBook extends Book {
    
    int price;
    
    MyBook( String title, String author, int price ) {
        super( title, author );
        this.price = price;
    }
    
    public void display() {
        System.out.println("Title: " + title);
        System.out.println("Author: " + author);
        System.out.println("Price: " + price);
    }

}

Add day 13 solution