import java.util.Scanner;

public class Main {

    private static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {

        solve();
    }

    private static void solve() {

        double l = scanner.nextInt();


        double base = l / 3;

        double result = Math.pow(base, 3) ;

        System.out.println(result);
    }
} import java.util.Scanner; Scanner java.util public class Main {

    private static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {

        solve();
    }

    private static void solve() {

        double l = scanner.nextInt();


        double base = l / 3;

        double result = Math.pow(base, 3) ;

        System.out.println(result);
    }
} Main private static Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) public static void main(String[] args) {

        solve();
    } main {

        solve();
    } solve() solve String[] args args private static void solve() {

        double l = scanner.nextInt();


        double base = l / 3;

        double result = Math.pow(base, 3) ;

        System.out.println(result);
    } solve {

        double l = scanner.nextInt();


        double base = l / 3;

        double result = Math.pow(base, 3) ;

        System.out.println(result);
    } double l = scanner.nextInt(); l scanner.nextInt() scanner.nextInt scanner double base = l / 3; base l / 3 l 3 double result = Math.pow(base, 3) ; result Math.pow(base, 3) Math.pow Math base 3 System.out.println(result) System.out.println System.out System System.out result public class Main {

    private static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {

        solve();
    }

    private static void solve() {

        double l = scanner.nextInt();


        double base = l / 3;

        double result = Math.pow(base, 3) ;

        System.out.println(result);
    }
} public class Main {

    private static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {

        solve();
    }

    private static void solve() {

        double l = scanner.nextInt();


        double base = l / 3;

        double result = Math.pow(base, 3) ;

        System.out.println(result);
    }
} Main
import java.util.Scanner;

public class Main {

    private static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {

        solve();
    }

    private static void solve() {

        double l = scanner.nextInt();


        double base = l / 3;

        double result = Math.pow(base, 3) ;

        System.out.println(result);
    }
}