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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>

using namespace std;
using ll = long long int;
using vec = vector<int>;

#define rep(i, n) for(int i = 0; i < (n); ++i)
#define Sort(a)   sort(a.begin(), a.end())
const int INF = 2147483647;
const ll  MOD = 1000000007;

int main() {
    int l; cin >> l;
    
    long double div = l / 3.0;

    cout << div << endl;

    long double ans;

    if(div * 3 == l) ans = div * div * div;
    else if(div * 3 > l) ans = div * div * (div - (0.000001));
    else                 ans = div * div * (div + (0.000001));

    cout << ans;

}