import java.util.Scanner;

public class Main {

    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);

        int L = sc.nextInt();
        double length = (double) L / 3;
        double ans = length * length * length;
        System.out.println(ans);
        
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);

        int L = sc.nextInt();
        double length = (double) L / 3;
        double ans = length * length * length;
        System.out.println(ans);
        
    }
} Main public static void main(String args[]){
        Scanner sc = new Scanner(System.in);

        int L = sc.nextInt();
        double length = (double) L / 3;
        double ans = length * length * length;
        System.out.println(ans);
        
    } main {
        Scanner sc = new Scanner(System.in);

        int L = sc.nextInt();
        double length = (double) L / 3;
        double ans = length * length * length;
        System.out.println(ans);
        
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int L = sc.nextInt(); L sc.nextInt() sc.nextInt sc double length = (double) L / 3; length (double) L / 3 (double) L 3 double ans = length * length * length; ans length * length * length length * length * length length length length System.out.println(ans) System.out.println System.out System System.out ans String args[] args public class Main {

    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);

        int L = sc.nextInt();
        double length = (double) L / 3;
        double ans = length * length * length;
        System.out.println(ans);
        
    }
} public class Main {

    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);

        int L = sc.nextInt();
        double length = (double) L / 3;
        double ans = length * length * length;
        System.out.println(ans);
        
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);

        int L = sc.nextInt();
        double length = (double) L / 3;
        double ans = length * length * length;
        System.out.println(ans);
        
    }
}
