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

			double pi = Math.PI;
			double area = r * r * pi;
			double circumference = 2 * r * pi;
			Console.WriteLine(area +" "+ circumference);
		}
	}
}