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

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

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

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

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

}