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 LIB;
using System;
using System.Linq;
using System.Text;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        double n = io.r<double>();
        io.w((n * n * Math.PI).ToString() + " " + (2 * n * Math.PI).ToString());
        io.wflush();
    }
}

namespace LIB
{
    public class io
    {
        private const int WMAX = 1000;
        private static StringBuilder S = new StringBuilder();
        public static T r<T>() { return util.parse<T>(r()); }
        public static T[] r<T>(char s = ' ') { return r().Split(s).Select(util.parse<T>).ToArray(); }
        public static T[] r<T>(int l) { T[] r = new T[l]; for (int i = 0; i < l; i++) { r[i] = r<T>(); } return r; }
        public static T[][] r<T>(int l, char s = ' ') { T[][] r = new T[l][]; for (int i = 0; i < l; i++) { r[i] = r<T>(s); } return r; }
        private static string r() { return Console.ReadLine(); }
        public static void w(object v, bool lf = true) { S.Append(util.parse<string>(v)); if (lf == true) { S.Append('\n'); } if (S.Length >= WMAX) { wflush(); } }
        public static void wflush() { Console.Write(S.ToString()); S.Length = 0; }
    }
    public class util
    {
        public static T parse<T>(object value) { return (T)(Convert.ChangeType(value, typeof(T))); }
    }
    public class memo<Key, Result>
    {
        private Dictionary<Key, Result> R;
        public memo() { R = new Dictionary<Key, Result>(); }
        public Result exec(Key k, Func<Key, Result> f) { Result r; if (R.ContainsKey(k)) { r = R[k]; } else { r = f(k); R.Add(k, r); } return r; }
    }
}