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