
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		double l = sc.nextDouble();
		
		System.out.printf("%f\n", Math.pow(l/3, 3));
	}

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

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		double l = sc.nextDouble();
		
		System.out.printf("%f\n", Math.pow(l/3, 3));
	}

} Main public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		double l = sc.nextDouble();
		
		System.out.printf("%f\n", Math.pow(l/3, 3));
	} main {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		double l = sc.nextDouble();
		
		System.out.printf("%f\n", Math.pow(l/3, 3));
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) double l = sc.nextDouble(); l sc.nextDouble() sc.nextDouble sc System.out.printf("%f\n", Math.pow(l/3, 3)) System.out.printf System.out System System.out "%f\n" Math.pow(l/3, 3) Math.pow Math l/3 l 3 3 String[] args args public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		double l = sc.nextDouble();
		
		System.out.printf("%f\n", Math.pow(l/3, 3));
	}

} public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		double l = sc.nextDouble();
		
		System.out.printf("%f\n", Math.pow(l/3, 3));
	}

} Main

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		double l = sc.nextDouble();
		
		System.out.printf("%f\n", Math.pow(l/3, 3));
	}

}
