import java.util.Scanner;
public class Main {
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    Double l;
    l = sc.nextDouble();
    l = l / 3.0;
    System.out.println(l*l*l);
  }
} import java.util.Scanner; Scanner java.util public class Main {
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    Double l;
    l = sc.nextDouble();
    l = l / 3.0;
    System.out.println(l*l*l);
  }
} Main public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    Double l;
    l = sc.nextDouble();
    l = l / 3.0;
    System.out.println(l*l*l);
  } main {
    Scanner sc = new Scanner(System.in);
    Double l;
    l = sc.nextDouble();
    l = l / 3.0;
    System.out.println(l*l*l);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Double l; l l = sc.nextDouble() l sc.nextDouble() sc.nextDouble sc l = l / 3.0 l l / 3.0 l 3.0 System.out.println(l*l*l) System.out.println System.out System System.out l*l*l l*l*l l l l String args[] args public class Main {
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    Double l;
    l = sc.nextDouble();
    l = l / 3.0;
    System.out.println(l*l*l);
  }
} public class Main {
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    Double l;
    l = sc.nextDouble();
    l = l / 3.0;
    System.out.println(l*l*l);
  }
} Main
import java.util.Scanner;
public class Main {
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    Double l;
    l = sc.nextDouble();
    l = l / 3.0;
    System.out.println(l*l*l);
  }
}
