class TestF {
	public static void main(String[] args)  {
		int x = 2;
		
		P p = new P(4);
		System.out.println("p.f(" + x + ") = " + p.f(x));
		
		D d = new D();
		System.out.println("d.f(" + x + ") = " + d.f(x));
		
		S s = new S(-3);
		System.out.println("s.f(" + x + ") = " + s.f(x));
	}
}

class P {
	int a;
	
	P(int parameter){
		a = parameter;
	}
	public int f(int y){ 
		return  a * y;
	}
}
class D extends P {
	
	D(){
		super(2);
	}
}
class S extends P {
	
	S(int parameter){
		super(parameter);
	}
	public int f(int y){ 
		return super.f(y) * a;
	}
}