import java.util.Scanner;

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

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