
import java.util.Scanner;


public class Main 
{ 
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        float n = sc.nextInt();
        float dim = n/3;
        System.out.printf("%f\n",dim*dim*dim);
    }
} import java.util.Scanner; Scanner java.util public class Main 
{ 
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        float n = sc.nextInt();
        float dim = n/3;
        System.out.printf("%f\n",dim*dim*dim);
    }
} Main public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        float n = sc.nextInt();
        float dim = n/3;
        System.out.printf("%f\n",dim*dim*dim);
    } main {
        Scanner sc = new Scanner(System.in);
        float n = sc.nextInt();
        float dim = n/3;
        System.out.printf("%f\n",dim*dim*dim);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) float n = sc.nextInt(); n sc.nextInt() sc.nextInt sc float dim = n/3; dim n/3 n 3 System.out.printf("%f\n",dim*dim*dim) System.out.printf System.out System System.out "%f\n" dim*dim*dim dim*dim*dim dim dim dim String[] args args public class Main 
{ 
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        float n = sc.nextInt();
        float dim = n/3;
        System.out.printf("%f\n",dim*dim*dim);
    }
} public class Main 
{ 
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        float n = sc.nextInt();
        float dim = n/3;
        System.out.printf("%f\n",dim*dim*dim);
    }
} Main

import java.util.Scanner;


public class Main 
{ 
    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        float n = sc.nextInt();
        float dim = n/3;
        System.out.printf("%f\n",dim*dim*dim);
    }
}
