import java.util.Scanner;

public class Main {
	public static void main(String args[]) {
		@SuppressWarnings("resource")
		double sum = new Scanner(System.in).nextDouble();
		
		System.out.println(Math.pow(sum / 3, 3));
		
	}
	
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String args[]) {
		@SuppressWarnings("resource")
		double sum = new Scanner(System.in).nextDouble();
		
		System.out.println(Math.pow(sum / 3, 3));
		
	}
	
} Main public static void main(String args[]) {
		@SuppressWarnings("resource")
		double sum = new Scanner(System.in).nextDouble();
		
		System.out.println(Math.pow(sum / 3, 3));
		
	} main {
		@SuppressWarnings("resource")
		double sum = new Scanner(System.in).nextDouble();
		
		System.out.println(Math.pow(sum / 3, 3));
		
	} @SuppressWarnings("resource")
		double sum = new Scanner(System.in).nextDouble(); sum new Scanner(System.in).nextDouble() new Scanner(System.in).nextDouble new Scanner(System.in) System.out.println(Math.pow(sum / 3, 3)) System.out.println System.out System System.out Math.pow(sum / 3, 3) Math.pow Math sum / 3 sum 3 3 String args[] args public class Main {
	public static void main(String args[]) {
		@SuppressWarnings("resource")
		double sum = new Scanner(System.in).nextDouble();
		
		System.out.println(Math.pow(sum / 3, 3));
		
	}
	
} public class Main {
	public static void main(String args[]) {
		@SuppressWarnings("resource")
		double sum = new Scanner(System.in).nextDouble();
		
		System.out.println(Math.pow(sum / 3, 3));
		
	}
	
} Main
import java.util.Scanner;

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