import java.util.Scanner;
public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
   int l=kbd.nextInt();
   double a=l*l*l;
  double A=a/27;
    System.out.printf("%.6f\n",A);
}
} import java.util.Scanner; Scanner java.util public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
   int l=kbd.nextInt();
   double a=l*l*l;
  double A=a/27;
    System.out.printf("%.6f\n",A);
}
} Main public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
   int l=kbd.nextInt();
   double a=l*l*l;
  double A=a/27;
    System.out.printf("%.6f\n",A);
} main {
   Scanner kbd = new Scanner(System.in);
   int l=kbd.nextInt();
   double a=l*l*l;
  double A=a/27;
    System.out.printf("%.6f\n",A);
} Scanner kbd = new Scanner(System.in); kbd new Scanner(System.in) int l=kbd.nextInt(); l kbd.nextInt() kbd.nextInt kbd double a=l*l*l; a l*l*l l*l*l l l l double A=a/27; A a/27 a 27 System.out.printf("%.6f\n",A) System.out.printf System.out System System.out "%.6f\n" A String[] args args public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
   int l=kbd.nextInt();
   double a=l*l*l;
  double A=a/27;
    System.out.printf("%.6f\n",A);
}
} public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
   int l=kbd.nextInt();
   double a=l*l*l;
  double A=a/27;
    System.out.printf("%.6f\n",A);
}
} Main
import java.util.Scanner;
public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
   int l=kbd.nextInt();
   double a=l*l*l;
  double A=a/27;
    System.out.printf("%.6f\n",A);
}
}