import java.util.Scanner;

public class Main {

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

        final int L = sc.nextInt();

        System.out.printf("%12f\n", Math.pow(L, 3) / 27);
    }
} import java.util.Scanner; Scanner java.util public class Main {

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

        final int L = sc.nextInt();

        System.out.printf("%12f\n", Math.pow(L, 3) / 27);
    }
} Main public static void main(String[] args) {
        final Scanner sc = new Scanner(System.in);

        final int L = sc.nextInt();

        System.out.printf("%12f\n", Math.pow(L, 3) / 27);
    } main {
        final Scanner sc = new Scanner(System.in);

        final int L = sc.nextInt();

        System.out.printf("%12f\n", Math.pow(L, 3) / 27);
    } final Scanner sc = new Scanner(System.in); sc new Scanner(System.in) final int L = sc.nextInt(); L sc.nextInt() sc.nextInt sc System.out.printf("%12f\n", Math.pow(L, 3) / 27) System.out.printf System.out System System.out "%12f\n" Math.pow(L, 3) / 27 Math.pow(L, 3) Math.pow Math L 3 27 String[] args args public class Main {

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

        final int L = sc.nextInt();

        System.out.printf("%12f\n", Math.pow(L, 3) / 27);
    }
} public class Main {

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

        final int L = sc.nextInt();

        System.out.printf("%12f\n", Math.pow(L, 3) / 27);
    }
} Main
import java.util.Scanner;

public class Main {

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

        final int L = sc.nextInt();

        System.out.printf("%12f\n", Math.pow(L, 3) / 27);
    }
}
