import java.util.*;
import java.util.stream.Collectors;

public class Main {

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

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

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

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

public class Main {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    double S = sc.nextDouble();
    System.out.println((double) Math.pow(S / 3, 3));
  }
}
