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 Python (3.8.2) (judge verdict: Accepted)

# import math
# import statistics
# import itertools
a=int(input())
# b=input()
# c=[]
# for i in a:
#     c.append(int(i))
# N,S,T= map(int,input().split())
# f = list(map(int,input().split()))
# g = [int(input()) for _ in range(N)]
# h = []
# for i in range(a):
#     h.append(list(map(int,input().split())))
# a = [[0] for _ in range(H)]#nizigen

print((a/3)**3)