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;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 競プロ_Csharp {
    class Program {
        static void Main(string[] args) {

            double r = NextDouble();
            double pi = Math.PI;

            double menseki = r * r * pi;
            double enshuu = 2 * r * pi;

            Println(menseki.ToString("F5") + " " + enshuu.ToString("F5"));

        }

        public static void Println (Object o) {
            Console.WriteLine(o);
        }

        public static string NextString() {
            return Console.ReadLine();
        }

        public static int NextInt () {
            return int.Parse(Console.ReadLine());
        }

        public static int[] NextInts () {
            string[] a = Console.ReadLine().Split();
            int[] b = new int[a.Length];
            for (int i = 0; i < a.Length; i++) {
                b[i] = int.Parse(a[i]);
            }
            return b;
        }

        public static double NextDouble () {
            return double.Parse(Console.ReadLine());
        }

    }
}