import java.util.Scanner;

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

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        System.out.println((double) n/3 * (double) n/3 * (double) n/3);
    }
}