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 Program {
    private static int Main() {
        var input = Console.ReadLine();
         
        double r = double.Parse( input );
 
        var area = r * r * Math.PI;
        var length = 2 * r * Math.PI;
 
        var output = string.Format( "{0} {1}", area, length );
        Console.WriteLine( output );
 
        return 0;
    }
}