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 Circle {
    public static void Main() {
        var r = double.Parse(Console.ReadLine());
        Console.WriteLine("{0:f6} {1:f6}", r * r * Math.PI, 2 * Math.PI * r);
    }
}