using System;

public class Program

{

    public static readonly double pi = 3.14; // can't modify the value of pi after setting it.

    public static void Main()

    {

        Console.WriteLine("Enter in the radius of a circle");

        string input = Console.ReadLine();

        double radius = Convert.ToDouble(input);

        Console.WriteLine("Area: " + CalculateArea(pi, radius));

        Console.WriteLine("Area of circle with radius 1: " + CalculateArea(pi));

    }

    public static double CalculateArea(double pi, double radius = 1.0)

    {

        return pi * radius * radius;

    }

}