import java.util.Scanner;
public class Main {
 
	public static void main(String[] args) {
 
		Scanner scan = new Scanner(System.in);
 
		int L = scan.nextInt();
      
      double b = (double) L/3;
      
        double a =0;
        a = b*b*b;
        
        System.out.println(a);
    }
} import java.util.Scanner; Scanner java.util public class Main {
 
	public static void main(String[] args) {
 
		Scanner scan = new Scanner(System.in);
 
		int L = scan.nextInt();
      
      double b = (double) L/3;
      
        double a =0;
        a = b*b*b;
        
        System.out.println(a);
    }
} Main public static void main(String[] args) {
 
		Scanner scan = new Scanner(System.in);
 
		int L = scan.nextInt();
      
      double b = (double) L/3;
      
        double a =0;
        a = b*b*b;
        
        System.out.println(a);
    } main {
 
		Scanner scan = new Scanner(System.in);
 
		int L = scan.nextInt();
      
      double b = (double) L/3;
      
        double a =0;
        a = b*b*b;
        
        System.out.println(a);
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int L = scan.nextInt(); L scan.nextInt() scan.nextInt scan double b = (double) L/3; b (double) L/3 (double) L 3 double a =0; a 0 a = b*b*b a b*b*b b*b*b b b b System.out.println(a) System.out.println System.out System System.out a String[] args args public class Main {
 
	public static void main(String[] args) {
 
		Scanner scan = new Scanner(System.in);
 
		int L = scan.nextInt();
      
      double b = (double) L/3;
      
        double a =0;
        a = b*b*b;
        
        System.out.println(a);
    }
} public class Main {
 
	public static void main(String[] args) {
 
		Scanner scan = new Scanner(System.in);
 
		int L = scan.nextInt();
      
      double b = (double) L/3;
      
        double a =0;
        a = b*b*b;
        
        System.out.println(a);
    }
} Main
import java.util.Scanner;
public class Main {
 
	public static void main(String[] args) {
 
		Scanner scan = new Scanner(System.in);
 
		int L = scan.nextInt();
      
      double b = (double) L/3;
      
        double a =0;
        a = b*b*b;
        
        System.out.println(a);
    }
}