using System;

abstract class realFunction             

{

    public abstract double calculate(double x);

    public abstract double calculate2(double c);

}

class squareFunction : realFunction

    {

        public override double calculate(double x)

        {return x*x;}

        public override double calculate2(double c)

        {return c+c;}

    }

public class Program

{

    public static void Main()

    {

        squareFunction s=new squareFunction();

        Console.Write(s.calculate(5));

        squareFunction c=new squareFunction();

        Console.WriteLine(s.calculate2(3));

    }

}