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