import java.util.*;

public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int L = sc.nextInt();
        double side = L / 3.0;
        System.out.println(side * side * side);
    }
} import java.util.*; util.* java public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int L = sc.nextInt();
        double side = L / 3.0;
        System.out.println(side * side * side);
    }
} Main static Scanner sc = new Scanner(System.in); sc new Scanner(System.in) public static void main(String[] args) {
        int L = sc.nextInt();
        double side = L / 3.0;
        System.out.println(side * side * side);
    } main {
        int L = sc.nextInt();
        double side = L / 3.0;
        System.out.println(side * side * side);
    } int L = sc.nextInt(); L sc.nextInt() sc.nextInt sc double side = L / 3.0; side L / 3.0 L 3.0 System.out.println(side * side * side) System.out.println System.out System System.out side * side * side side * side * side side side side String[] args args public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int L = sc.nextInt();
        double side = L / 3.0;
        System.out.println(side * side * side);
    }
} public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int L = sc.nextInt();
        double side = L / 3.0;
        System.out.println(side * side * side);
    }
} Main
import java.util.*;

public class Main {
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        int L = sc.nextInt();
        double side = L / 3.0;
        System.out.println(side * side * side);
    }
}
