abstract class animal
{
    public abstract void sound();
}
class dog extends animal
{
    public void sound()
    {
    System.out.println("dog is barking");
    }
}
class tiger extends animal
{
    public void sound()
    {
    System.out.println("dog is tiger");
        
    }
    
}
class S{
    public static void main(String[] args){
        dog r= new dog();
        tiger k= new tiger();
        
        r.sound();
        k.sound();
    }
}