import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double l = sc.nextDouble();
        double d = (l * l * l) / 27;
        System.out.printf("%.12f\n" ,d);
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double l = sc.nextDouble();
        double d = (l * l * l) / 27;
        System.out.printf("%.12f\n" ,d);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double l = sc.nextDouble();
        double d = (l * l * l) / 27;
        System.out.printf("%.12f\n" ,d);
    } main {
        Scanner sc = new Scanner(System.in);
        double l = sc.nextDouble();
        double d = (l * l * l) / 27;
        System.out.printf("%.12f\n" ,d);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) double l = sc.nextDouble(); l sc.nextDouble() sc.nextDouble sc double d = (l * l * l) / 27; d (l * l * l) / 27 (l * l * l) l * l * l l l l 27 System.out.printf("%.12f\n" ,d) System.out.printf System.out System System.out "%.12f\n" d String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double l = sc.nextDouble();
        double d = (l * l * l) / 27;
        System.out.printf("%.12f\n" ,d);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double l = sc.nextDouble();
        double d = (l * l * l) / 27;
        System.out.printf("%.12f\n" ,d);
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double l = sc.nextDouble();
        double d = (l * l * l) / 27;
        System.out.printf("%.12f\n" ,d);
    }
}