Problem:
Circle

Write a program which calculates the area and circumference of a circle for given radius r.

Input

A real number r is given.

Output

Print the area and circumference of the circle in a line. Put a single space between them. The output should not contain an absolute error greater than 10-5.

Constraints

0 < r < 10000

Sample Input 1

2

Sample Output 1

12.566371 12.566371

Sample Input 2

3

Sample Output 2

28.274334 18.849556

Solution in C# (judge verdict: Accepted)

using System;

public class Circle
{
    //????????????????????¢?????¨??¨?????????????±???????
    static void Main(string[] args)
    {
        /*---??£?¨???¨---*/
        double radius;

        /*---??£?¨???¨---*/

        /*????????????*/
        radius = double.Parse(Console.ReadLine());

        /*----?¨??????¨----*/
        //??¢???
        Console.WriteLine((radius * radius * Math.PI).ToString("F5"));

        //?????¨
        Console.WriteLine((2 * radius * Math.PI).ToString("F5"));
    }
}