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;

namespace Test
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            var input = Console.ReadLine();
            var r = double.Parse(input);

            var area = r * r * Math.PI;
            var circumference = 2 * r * Math.PI;

            Console.WriteLine("{0:f6} {1:f6}",area,circumference);
        }
    }
}