using System;

namespace DeclaringConstants

{                   

    public class Program

    {

        public static void Main(string[] args)

        {

            const double pi = 3.14159;

            //constant declaration

            double r;

            Console.WriteLine("Enter Radius: ");

            r = Convert.ToDouble(Console.ReadLine());

            double areaCircle = pi * r * r;

            Console.WriteLine("Radius: {0}, Area: {1}", r, areaCircle); 

        }

    }

}