public class Virtual {
    public static void main(String[] args) {
        Tall giraffe = new Tall();
        Short penguin = new Short();
        System.out.print("giraffe's height is ");
        giraffe.height();
        System.out.print("penguin's height is ");
        penguin.height();
    }
}
class Tall {
    public void printHeight() {
        System.out.println("tall");
    }
    public void height() {
        this.printHeight();
    }
}
class Short extends Tall {
    public void printHeight() {
        System.out.println("short");
    }
}