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