import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {
			
			double l = sc.nextDouble();
			
			double edge = l/3;
			
			System.out.println(String.format("%f", Math.pow(edge, 3)));
		}
	}

} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {
			
			double l = sc.nextDouble();
			
			double edge = l/3;
			
			System.out.println(String.format("%f", Math.pow(edge, 3)));
		}
	}

} Main public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {
			
			double l = sc.nextDouble();
			
			double edge = l/3;
			
			System.out.println(String.format("%f", Math.pow(edge, 3)));
		}
	} main {
		try(Scanner sc = new Scanner(System.in)) {
			
			double l = sc.nextDouble();
			
			double edge = l/3;
			
			System.out.println(String.format("%f", Math.pow(edge, 3)));
		}
	} try(Scanner sc = new Scanner(System.in)) {
			
			double l = sc.nextDouble();
			
			double edge = l/3;
			
			System.out.println(String.format("%f", Math.pow(edge, 3)));
		} {
			
			double l = sc.nextDouble();
			
			double edge = l/3;
			
			System.out.println(String.format("%f", Math.pow(edge, 3)));
		} Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) double l = sc.nextDouble(); l sc.nextDouble() sc.nextDouble sc double edge = l/3; edge l/3 l 3 System.out.println(String.format("%f", Math.pow(edge, 3))) System.out.println System.out System System.out String.format("%f", Math.pow(edge, 3)) String.format String "%f" Math.pow(edge, 3) Math.pow Math edge 3 String[] args args public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {
			
			double l = sc.nextDouble();
			
			double edge = l/3;
			
			System.out.println(String.format("%f", Math.pow(edge, 3)));
		}
	}

} public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {
			
			double l = sc.nextDouble();
			
			double edge = l/3;
			
			System.out.println(String.format("%f", Math.pow(edge, 3)));
		}
	}

} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {
			
			double l = sc.nextDouble();
			
			double edge = l/3;
			
			System.out.println(String.format("%f", Math.pow(edge, 3)));
		}
	}

}