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;

class ITP1_4_B
{
    public static void Main()
    {
        double r = double.Parse(Console.ReadLine());
        double area = r * r * Math.PI;
        double length = r * 2 * Math.PI;
        Console.WriteLine(area + " " + length);
    }
}