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

public class Main {

	public static void main(String[] args) {
		Scanner sca = new Scanner(System.in);

		int l = sca.nextInt();

		double i = l/3.0;
		double j = l/3.0;
		double k = l/3.0;
		double max = i*j*k;
		BigDecimal bd = new BigDecimal(max);

		System.out.println(bd.setScale(8, RoundingMode.DOWN));

		// 後始末
		sca.close();
	}
} import java.math.BigDecimal; BigDecimal java.math import java.math.RoundingMode; RoundingMode java.math import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sca = new Scanner(System.in);

		int l = sca.nextInt();

		double i = l/3.0;
		double j = l/3.0;
		double k = l/3.0;
		double max = i*j*k;
		BigDecimal bd = new BigDecimal(max);

		System.out.println(bd.setScale(8, RoundingMode.DOWN));

		// 後始末
		sca.close();
	}
} Main public static void main(String[] args) {
		Scanner sca = new Scanner(System.in);

		int l = sca.nextInt();

		double i = l/3.0;
		double j = l/3.0;
		double k = l/3.0;
		double max = i*j*k;
		BigDecimal bd = new BigDecimal(max);

		System.out.println(bd.setScale(8, RoundingMode.DOWN));

		// 後始末
		sca.close();
	} main {
		Scanner sca = new Scanner(System.in);

		int l = sca.nextInt();

		double i = l/3.0;
		double j = l/3.0;
		double k = l/3.0;
		double max = i*j*k;
		BigDecimal bd = new BigDecimal(max);

		System.out.println(bd.setScale(8, RoundingMode.DOWN));

		// 後始末
		sca.close();
	} Scanner sca = new Scanner(System.in); sca new Scanner(System.in) int l = sca.nextInt(); l sca.nextInt() sca.nextInt sca double i = l/3.0; i l/3.0 l 3.0 double j = l/3.0; j l/3.0 l 3.0 double k = l/3.0; k l/3.0 l 3.0 double max = i*j*k; max i*j*k i*j*k i j k BigDecimal bd = new BigDecimal(max); bd new BigDecimal(max) System.out.println(bd.setScale(8, RoundingMode.DOWN)) System.out.println System.out System System.out bd.setScale(8, RoundingMode.DOWN) bd.setScale bd 8 RoundingMode.DOWN RoundingMode RoundingMode.DOWN sca.close() sca.close sca String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sca = new Scanner(System.in);

		int l = sca.nextInt();

		double i = l/3.0;
		double j = l/3.0;
		double k = l/3.0;
		double max = i*j*k;
		BigDecimal bd = new BigDecimal(max);

		System.out.println(bd.setScale(8, RoundingMode.DOWN));

		// 後始末
		sca.close();
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sca = new Scanner(System.in);

		int l = sca.nextInt();

		double i = l/3.0;
		double j = l/3.0;
		double k = l/3.0;
		double max = i*j*k;
		BigDecimal bd = new BigDecimal(max);

		System.out.println(bd.setScale(8, RoundingMode.DOWN));

		// 後始末
		sca.close();
	}
} Main
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sca = new Scanner(System.in);

		int l = sca.nextInt();

		double i = l/3.0;
		double j = l/3.0;
		double k = l/3.0;
		double max = i*j*k;
		BigDecimal bd = new BigDecimal(max);

		System.out.println(bd.setScale(8, RoundingMode.DOWN));

		// 後始末
		sca.close();
	}
}