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

public class Main {

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

		BigDecimal L = new BigDecimal(sc.nextLine());
		BigDecimal div = new BigDecimal(3.0);
		MathContext mc = new MathContext(10,RoundingMode.HALF_UP);
		BigDecimal cutNum = L.divide(div, mc);


		System.out.println(cutNum.multiply(cutNum).multiply(cutNum));

	}
} import java.math.BigDecimal; BigDecimal java.math import java.math.MathContext; MathContext 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 sc = new Scanner(System.in);

		BigDecimal L = new BigDecimal(sc.nextLine());
		BigDecimal div = new BigDecimal(3.0);
		MathContext mc = new MathContext(10,RoundingMode.HALF_UP);
		BigDecimal cutNum = L.divide(div, mc);


		System.out.println(cutNum.multiply(cutNum).multiply(cutNum));

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

		BigDecimal L = new BigDecimal(sc.nextLine());
		BigDecimal div = new BigDecimal(3.0);
		MathContext mc = new MathContext(10,RoundingMode.HALF_UP);
		BigDecimal cutNum = L.divide(div, mc);


		System.out.println(cutNum.multiply(cutNum).multiply(cutNum));

	} main {
		Scanner sc = new Scanner(System.in);

		BigDecimal L = new BigDecimal(sc.nextLine());
		BigDecimal div = new BigDecimal(3.0);
		MathContext mc = new MathContext(10,RoundingMode.HALF_UP);
		BigDecimal cutNum = L.divide(div, mc);


		System.out.println(cutNum.multiply(cutNum).multiply(cutNum));

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) BigDecimal L = new BigDecimal(sc.nextLine()); L new BigDecimal(sc.nextLine()) BigDecimal div = new BigDecimal(3.0); div new BigDecimal(3.0) MathContext mc = new MathContext(10,RoundingMode.HALF_UP); mc new MathContext(10,RoundingMode.HALF_UP) BigDecimal cutNum = L.divide(div, mc); cutNum L.divide(div, mc) L.divide L div mc System.out.println(cutNum.multiply(cutNum).multiply(cutNum)) System.out.println System.out System System.out cutNum.multiply(cutNum).multiply(cutNum) cutNum.multiply(cutNum).multiply cutNum.multiply(cutNum) cutNum.multiply cutNum cutNum cutNum String[] args args public class Main {

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

		BigDecimal L = new BigDecimal(sc.nextLine());
		BigDecimal div = new BigDecimal(3.0);
		MathContext mc = new MathContext(10,RoundingMode.HALF_UP);
		BigDecimal cutNum = L.divide(div, mc);


		System.out.println(cutNum.multiply(cutNum).multiply(cutNum));

	}
} public class Main {

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

		BigDecimal L = new BigDecimal(sc.nextLine());
		BigDecimal div = new BigDecimal(3.0);
		MathContext mc = new MathContext(10,RoundingMode.HALF_UP);
		BigDecimal cutNum = L.divide(div, mc);


		System.out.println(cutNum.multiply(cutNum).multiply(cutNum));

	}
} Main
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
import java.util.Scanner;

public class Main {

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

		BigDecimal L = new BigDecimal(sc.nextLine());
		BigDecimal div = new BigDecimal(3.0);
		MathContext mc = new MathContext(10,RoundingMode.HALF_UP);
		BigDecimal cutNum = L.divide(div, mc);


		System.out.println(cutNum.multiply(cutNum).multiply(cutNum));

	}
}