import java.util.Scanner;

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

        int L = s.nextInt();

        System.out.println((double) L * L * L / 27);
        s.close();
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);

        int L = s.nextInt();

        System.out.println((double) L * L * L / 27);
        s.close();
    }
} Main public static void main(String[] args) {
        Scanner s = new Scanner(System.in);

        int L = s.nextInt();

        System.out.println((double) L * L * L / 27);
        s.close();
    } main {
        Scanner s = new Scanner(System.in);

        int L = s.nextInt();

        System.out.println((double) L * L * L / 27);
        s.close();
    } Scanner s = new Scanner(System.in); s new Scanner(System.in) int L = s.nextInt(); L s.nextInt() s.nextInt s System.out.println((double) L * L * L / 27) System.out.println System.out System System.out (double) L * L * L / 27 (double) L * L * L (double) L * L * L (double) L L L 27 s.close() s.close s String[] args args public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);

        int L = s.nextInt();

        System.out.println((double) L * L * L / 27);
        s.close();
    }
} public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);

        int L = s.nextInt();

        System.out.println((double) L * L * L / 27);
        s.close();
    }
} Main
import java.util.Scanner;

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

        int L = s.nextInt();

        System.out.println((double) L * L * L / 27);
        s.close();
    }
}