
import java.util.Scanner;

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

}
//36926037.000000000000 import java.util.Scanner; Scanner java.util public class Main {
static Scanner s = new Scanner(System.in);
	public static void main(String[] args) {
		double l = s.nextDouble();
		
		double k = l/3;
		double v = Math.pow(l/3,3);
		System.out.println(v);
	}

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

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

} Main

import java.util.Scanner;

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

}
//36926037.000000000000