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 Rust (1.42.0) (judge verdict: Wrong Answer)

#[warn(unused_imports)]
use proconio::{fastout, input, marker::*};

#[fastout]
fn main() {
    input! {
        l: usize,
    }

    let mut ans = 0f64;
    let l = l * 10;

    for x in 0..l+1 {
        for y in 0..l-x+1 {
            let z = (l - x - y) as f64 / 10.0;
            let x = x as f64 / 10.0;
            let y = y as f64 / 10.0;
            ans = ans.max(x * y * z);
        }
    }

    println!("{}", ans);
}