//only one parent class remaining all are child classes
class animal{
    animal(){
        System.out.println("this is animal class");
    }
    public void eat(){
        System.out.println("it is eating");
    }
} 
class cat extends animal{
    cat(){
        System.out.println("this is cat class");
    }
}
class fish extends animal{
    fish(){
        System.out.println("this is fish class");
    }
}
public class Main{
    public static void main(String[] args){
        cat kitty=new cat();
        kitty.eat();
    }
}