import java.util.*;
public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    double l = sc.nextDouble();
    
    double num =  l/3;
    
    System.out.println(Math.pow(num,3));
    
  }
} import java.util.*; util.* java public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    double l = sc.nextDouble();
    
    double num =  l/3;
    
    System.out.println(Math.pow(num,3));
    
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    double l = sc.nextDouble();
    
    double num =  l/3;
    
    System.out.println(Math.pow(num,3));
    
  } main {
    Scanner sc = new Scanner(System.in);
    double l = sc.nextDouble();
    
    double num =  l/3;
    
    System.out.println(Math.pow(num,3));
    
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) double l = sc.nextDouble(); l sc.nextDouble() sc.nextDouble sc double num =  l/3; num l/3 l 3 System.out.println(Math.pow(num,3)) System.out.println System.out System System.out Math.pow(num,3) Math.pow Math num 3 String[] args args public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    double l = sc.nextDouble();
    
    double num =  l/3;
    
    System.out.println(Math.pow(num,3));
    
  }
} public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    double l = sc.nextDouble();
    
    double num =  l/3;
    
    System.out.println(Math.pow(num,3));
    
  }
} Main
import java.util.*;
public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    double l = sc.nextDouble();
    
    double num =  l/3;
    
    System.out.println(Math.pow(num,3));
    
  }
}