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<bits/stdc++.h>
using namespace std;

int main()
{
  int l;
  cin>>l;
  int t=l;
  int count=0;
  //if(l<=3)
  //{
  //    float m=1;
  //     cout<<fixed<<setprecision(12)<<m;
  //     return 0;
 // }
  while(t%3!=0)
  {
      t--;
      count++;
  }
  float a=(l-count)/3;
  float b=(l-count)/3;
  float c=(l-count)/3;
  if(count==2)
  {
      a++;
      b++;
  }
  if(count==1)
  {
      a++;
  }

  float k=a*b*c;

  cout<<fixed<<setprecision(12)<<k;

  return 0;
}