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 _4_B {
    class Program {
        static void Main (string[] args) {
            var pi = 3.141592653589d;
            var r = Convert.ToDouble (Console.ReadLine ());
            var area = pi * r * r;
            var circumference = 2 * pi * r;

            Console.WriteLine ($"{area} {circumference}");
        }
    }
}