Problem:
Score : 300 points

Problem Statement

Given is a positive integer L.
Find the maximum possible volume of a rectangular cuboid whose sum of the dimensions (not necessarily integers) is L.

Constraints

1 ≤ L ≤ 1000

L is an integer.

Input

Input is given from Standard Input in the following format:

L

Output

Print the maximum possible volume of a rectangular cuboid whose sum of the dimensions (not necessarily integers) is L.
Your output is considered correct if its absolute or relative error from our answer is at most 10^{-6}.

Sample Input 1

3

Sample Output 1

1.000000000000

For example, a rectangular cuboid whose dimensions are 0.8, 1, and 1.2 has a volume of 0.96.

On the other hand, if the dimensions are 1, 1, and 1, the volume of the rectangular cuboid is 1, which is greater.

Sample Input 2

999

Sample Output 2

36926037.000000000000

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

namespace Test
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;

    public class Test
    {
        public static void Main(string[] args)
        {
            var t = new Test();
            var L = int.Parse(Console.ReadLine());
            decimal l = L / 3.0m;
            decimal ans = l * l * l;
            Console.WriteLine(ans);
        }

        public int Gcd(int a, int b)
        {
            for (var i = b; i > 1; i -= 1)
            {
                if (a % i == 0 && b % i == 0)
                {
                    return i;
                }
            }
            return 1;
        }

        public string[] ReadInput()
        {
            return Console.ReadLine().Split(' ');
        }

        public List<int> ConvertIntList(string[] x)
        {
            var convertedList = new List<int>(x.Length);
            for (var i = 0; i < x.Length; i++)
            {
                convertedList.Add(int.Parse(x[i]));
            }

            return convertedList;
        }

        public List<double> ConvertDoubleList(string[] x)
        {
            var convertedList = new List<double>(x.Length);
            for (var i = 0; i < x.Length; i++)
            {
                convertedList.Add(double.Parse(x[i]));
            }

            return convertedList;
        }

        public List<long> ConvertLongList(string[] x)
        {
            var convertedList = new List<long>(x.Length);
            for (var i = 0; i < x.Length; i++)
            {
                convertedList.Add(long.Parse(x[i]));
            }

            return convertedList;
        }

        public int CountContainWords(string source, string word)
        {
            var count = 0;
            var loopCount = source.Length - (word.Length - 1);
            for (var i = 0; i < loopCount; i++)
            {
                if (source.Substring(i, word.Length) == word)
                {
                    count++;
                }
            }
            return count;
        }
    }
}