题目描述
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}.
Examples
Input
3
Output
1.000000000000
Input
999
Output
36926037.000000000000
输入格式
见题面
输出格式
见题面
样例输入
999
样例输出
36926037.000000000000