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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner kb = new Scanner(System.in);
		int l = kb.nextInt();
		double k1 = 1;
		double k2 = 1;
		double k3 = l - 2;
		double sum = k1 * k2 * k3;
		//System.out.println(sum);
		while (k1 <= l-2) {
			k2 = k1;
			k3 = l - k1 - k2;
			while (k2 <= k3) {
				double sum2 = k1 * k2 * k3;
				if (sum < sum2)
					sum = sum2;
				k2 += 1;
				k3 -= 1;
			}
			k1 += 1;
		}
		System.out.println(sum);
		kb.close();
	}

}