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: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            //[summary]C - Maximum Volume
            int L = int.Parse(Console.ReadLine());

            if (L == 1)
            {
                Console.WriteLine(0.036);
            }
            else if (L == 2)
            {
                Console.WriteLine(0.294);
            }
            else
            {
                int max = 0;

                for (int i = 1; i <= L - 2; i++)
                {
                    for (int j = 1; i + j <= L - 1; j++)
                    {
                        int k = L - i - j;

                        max = Math.Max(max, i * j * k);

                        //if (i * j * k == 294)
                        //{
                        //    Console.WriteLine("{0} {1} {2}", i, j, k);
                        //}
                    }
                }

                Console.WriteLine(max);
            }
        }
    }
}