import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		try {
			float L = Float.parseFloat(sc.next());
			float ippen = L / 3;
			float ans = ippen * ippen * ippen;
			System.out.println(ans);

		} finally

		{
			sc.close();
		}
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		try {
			float L = Float.parseFloat(sc.next());
			float ippen = L / 3;
			float ans = ippen * ippen * ippen;
			System.out.println(ans);

		} finally

		{
			sc.close();
		}
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		try {
			float L = Float.parseFloat(sc.next());
			float ippen = L / 3;
			float ans = ippen * ippen * ippen;
			System.out.println(ans);

		} finally

		{
			sc.close();
		}
	} main {
		Scanner sc = new Scanner(System.in);
		try {
			float L = Float.parseFloat(sc.next());
			float ippen = L / 3;
			float ans = ippen * ippen * ippen;
			System.out.println(ans);

		} finally

		{
			sc.close();
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) try {
			float L = Float.parseFloat(sc.next());
			float ippen = L / 3;
			float ans = ippen * ippen * ippen;
			System.out.println(ans);

		} finally

		{
			sc.close();
		} {
			sc.close();
		} sc.close() sc.close sc {
			float L = Float.parseFloat(sc.next());
			float ippen = L / 3;
			float ans = ippen * ippen * ippen;
			System.out.println(ans);

		} float L = Float.parseFloat(sc.next()); L Float.parseFloat(sc.next()) Float.parseFloat Float sc.next() sc.next sc float ippen = L / 3; ippen L / 3 L 3 float ans = ippen * ippen * ippen; ans ippen * ippen * ippen ippen * ippen * ippen ippen ippen ippen System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		try {
			float L = Float.parseFloat(sc.next());
			float ippen = L / 3;
			float ans = ippen * ippen * ippen;
			System.out.println(ans);

		} finally

		{
			sc.close();
		}
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		try {
			float L = Float.parseFloat(sc.next());
			float ippen = L / 3;
			float ans = ippen * ippen * ippen;
			System.out.println(ans);

		} finally

		{
			sc.close();
		}
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		try {
			float L = Float.parseFloat(sc.next());
			float ippen = L / 3;
			float ans = ippen * ippen * ippen;
			System.out.println(ans);

		} finally

		{
			sc.close();
		}
	}

}
