import java.util.Scanner;

public class Main{
	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		int n = Integer.parseInt(scanner.nextLine());

		double x = n / 3.0;


		System.out.println(x * x * x);

	}
} import java.util.Scanner; Scanner java.util public class Main{
	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		int n = Integer.parseInt(scanner.nextLine());

		double x = n / 3.0;


		System.out.println(x * x * x);

	}
} Main public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		int n = Integer.parseInt(scanner.nextLine());

		double x = n / 3.0;


		System.out.println(x * x * x);

	} main {

		Scanner scanner = new Scanner(System.in);

		int n = Integer.parseInt(scanner.nextLine());

		double x = n / 3.0;


		System.out.println(x * x * x);

	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int n = Integer.parseInt(scanner.nextLine()); n Integer.parseInt(scanner.nextLine()) Integer.parseInt Integer scanner.nextLine() scanner.nextLine scanner double x = n / 3.0; x n / 3.0 n 3.0 System.out.println(x * x * x) System.out.println System.out System System.out x * x * x x * x * x x x x String[] args args public class Main{
	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		int n = Integer.parseInt(scanner.nextLine());

		double x = n / 3.0;


		System.out.println(x * x * x);

	}
} public class Main{
	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		int n = Integer.parseInt(scanner.nextLine());

		double x = n / 3.0;


		System.out.println(x * x * x);

	}
} Main
import java.util.Scanner;

public class Main{
	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);

		int n = Integer.parseInt(scanner.nextLine());

		double x = n / 3.0;


		System.out.println(x * x * x);

	}
}