import java.util.*;

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

        int l = sc.nextInt();
        double d = l / 3.0;

        System.out.println(Math.pow(d, 3));

    }
} import java.util.*; util.* java public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int l = sc.nextInt();
        double d = l / 3.0;

        System.out.println(Math.pow(d, 3));

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

        int l = sc.nextInt();
        double d = l / 3.0;

        System.out.println(Math.pow(d, 3));

    } main {
        Scanner sc = new Scanner(System.in);

        int l = sc.nextInt();
        double d = l / 3.0;

        System.out.println(Math.pow(d, 3));

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int l = sc.nextInt(); l sc.nextInt() sc.nextInt sc double d = l / 3.0; d l / 3.0 l 3.0 System.out.println(Math.pow(d, 3)) System.out.println System.out System System.out Math.pow(d, 3) Math.pow Math d 3 String[] args args public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int l = sc.nextInt();
        double d = l / 3.0;

        System.out.println(Math.pow(d, 3));

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

        int l = sc.nextInt();
        double d = l / 3.0;

        System.out.println(Math.pow(d, 3));

    }
} Main
import java.util.*;

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

        int l = sc.nextInt();
        double d = l / 3.0;

        System.out.println(Math.pow(d, 3));

    }
}
