

import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int l = scan.nextInt();
		BigDecimal bigL = new BigDecimal(l * l * l);
		BigDecimal big27 = new BigDecimal(27.000000);

		BigDecimal result = bigL.divide(big27, 6, BigDecimal.ROUND_HALF_UP);

		System.out.println(result);
	}

} import java.math.BigDecimal; BigDecimal java.math import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int l = scan.nextInt();
		BigDecimal bigL = new BigDecimal(l * l * l);
		BigDecimal big27 = new BigDecimal(27.000000);

		BigDecimal result = bigL.divide(big27, 6, BigDecimal.ROUND_HALF_UP);

		System.out.println(result);
	}

} Main public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int l = scan.nextInt();
		BigDecimal bigL = new BigDecimal(l * l * l);
		BigDecimal big27 = new BigDecimal(27.000000);

		BigDecimal result = bigL.divide(big27, 6, BigDecimal.ROUND_HALF_UP);

		System.out.println(result);
	} main {

		Scanner scan = new Scanner(System.in);

		int l = scan.nextInt();
		BigDecimal bigL = new BigDecimal(l * l * l);
		BigDecimal big27 = new BigDecimal(27.000000);

		BigDecimal result = bigL.divide(big27, 6, BigDecimal.ROUND_HALF_UP);

		System.out.println(result);
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int l = scan.nextInt(); l scan.nextInt() scan.nextInt scan BigDecimal bigL = new BigDecimal(l * l * l); bigL new BigDecimal(l * l * l) BigDecimal big27 = new BigDecimal(27.000000); big27 new BigDecimal(27.000000) BigDecimal result = bigL.divide(big27, 6, BigDecimal.ROUND_HALF_UP); result bigL.divide(big27, 6, BigDecimal.ROUND_HALF_UP) bigL.divide bigL big27 6 BigDecimal.ROUND_HALF_UP BigDecimal BigDecimal.ROUND_HALF_UP System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {
	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int l = scan.nextInt();
		BigDecimal bigL = new BigDecimal(l * l * l);
		BigDecimal big27 = new BigDecimal(27.000000);

		BigDecimal result = bigL.divide(big27, 6, BigDecimal.ROUND_HALF_UP);

		System.out.println(result);
	}

} public class Main {
	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int l = scan.nextInt();
		BigDecimal bigL = new BigDecimal(l * l * l);
		BigDecimal big27 = new BigDecimal(27.000000);

		BigDecimal result = bigL.divide(big27, 6, BigDecimal.ROUND_HALF_UP);

		System.out.println(result);
	}

} Main


import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int l = scan.nextInt();
		BigDecimal bigL = new BigDecimal(l * l * l);
		BigDecimal big27 = new BigDecimal(27.000000);

		BigDecimal result = bigL.divide(big27, 6, BigDecimal.ROUND_HALF_UP);

		System.out.println(result);
	}

}
