import java.util.Scanner;
public class Main{
    public static void main(String[]args){
        Scanner scan = new Scanner(System.in);
        double l=scan.nextDouble();
        double tmp = l/3;
        System.out.println(tmp*tmp*tmp);
    }
} import java.util.Scanner; Scanner java.util public class Main{
    public static void main(String[]args){
        Scanner scan = new Scanner(System.in);
        double l=scan.nextDouble();
        double tmp = l/3;
        System.out.println(tmp*tmp*tmp);
    }
} Main public static void main(String[]args){
        Scanner scan = new Scanner(System.in);
        double l=scan.nextDouble();
        double tmp = l/3;
        System.out.println(tmp*tmp*tmp);
    } main {
        Scanner scan = new Scanner(System.in);
        double l=scan.nextDouble();
        double tmp = l/3;
        System.out.println(tmp*tmp*tmp);
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) double l=scan.nextDouble(); l scan.nextDouble() scan.nextDouble scan double tmp = l/3; tmp l/3 l 3 System.out.println(tmp*tmp*tmp) System.out.println System.out System System.out tmp*tmp*tmp tmp*tmp*tmp tmp tmp tmp String[]args args public class Main{
    public static void main(String[]args){
        Scanner scan = new Scanner(System.in);
        double l=scan.nextDouble();
        double tmp = l/3;
        System.out.println(tmp*tmp*tmp);
    }
} public class Main{
    public static void main(String[]args){
        Scanner scan = new Scanner(System.in);
        double l=scan.nextDouble();
        double tmp = l/3;
        System.out.println(tmp*tmp*tmp);
    }
} Main
import java.util.Scanner;
public class Main{
    public static void main(String[]args){
        Scanner scan = new Scanner(System.in);
        double l=scan.nextDouble();
        double tmp = l/3;
        System.out.println(tmp*tmp*tmp);
    }
}