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)

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

class C {
    static StreamWriter Out = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
    static void Main(string[] args) {
        double L;
        Input(out L);
        double r = L / 3;
        Print(r * r * r);
        Out.Flush();
    }
    static T ChangeT<T>(string s) => (T)Convert.ChangeType(s, typeof(T));
    static void Input<A>(out A a) {
        var words = Console.ReadLine().Split(new[] { ' ' }, options: StringSplitOptions.RemoveEmptyEntries);
        a = ChangeT<A>(words[0]);
    }
    static void Input<A, B>(out A a, out B b) {
        var words = Console.ReadLine().Split(new[] { ' ' }, options: StringSplitOptions.RemoveEmptyEntries);
        a = ChangeT<A>(words[0]);
        b = ChangeT<B>(words[1]);
    }
    static void Input<A, B, C>(out A a, out B b, out C c) {
        var words = Console.ReadLine().Split(new[] { ' ' }, options: StringSplitOptions.RemoveEmptyEntries);
        a = ChangeT<A>(words[0]);
        b = ChangeT<B>(words[1]);
        c = ChangeT<C>(words[2]);
    }
    static void Input<A, B, C, D>(out A a, out B b, out C c, out D d) {
        var words = Console.ReadLine().Split(new[] { ' ' }, options: StringSplitOptions.RemoveEmptyEntries);
        a = ChangeT<A>(words[0]);
        b = ChangeT<B>(words[1]);
        c = ChangeT<C>(words[2]);
        d = ChangeT<D>(words[3]);
    }
    static void Input<A, B, C, D, E>(out A a, out B b, out C c, out D d, out E e) {
        var words = Console.ReadLine().Split(new[] { ' ' }, options: StringSplitOptions.RemoveEmptyEntries);
        a = ChangeT<A>(words[0]);
        b = ChangeT<B>(words[1]);
        c = ChangeT<C>(words[2]);
        d = ChangeT<D>(words[3]);
        e = ChangeT<E>(words[4]);
    }
    static void Input<A, B, C, D, E, F>(out A a, out B b, out C c, out D d, out E e, out F f) {
        var words = Console.ReadLine().Split(new[] { ' ' }, options: StringSplitOptions.RemoveEmptyEntries);
        a = ChangeT<A>(words[0]);
        b = ChangeT<B>(words[1]);
        c = ChangeT<C>(words[2]);
        d = ChangeT<D>(words[3]);
        e = ChangeT<E>(words[4]);
        f = ChangeT<F>(words[5]);
    }
    static void Inputs<T>(out T[] array) {
        array = Console.ReadLine().Split(new[] { ' ' }, options: StringSplitOptions.RemoveEmptyEntries).Select(s => ChangeT<T>(s)).ToArray();
    }
    static void Print<T>(T s) => Out.WriteLine(s);
    static void Print<T>(params T[] s) => Out.WriteLine(string.Join(" ", s));
    static void Print<T>(IEnumerable<T> e) => Out.WriteLine(string.Join(" ", e));
}