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

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

		Scanner sc =new Scanner(System.in);
		double l=sc.nextDouble();
		BigDecimal side1 = new BigDecimal(l/3);
		BigDecimal side2 = new BigDecimal(l/3);
		BigDecimal side3 = new BigDecimal(l/3);
		System.out.println(side1.multiply(side2).multiply(side3));
	}
} import java.math.BigDecimal; BigDecimal java.math import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {

		Scanner sc =new Scanner(System.in);
		double l=sc.nextDouble();
		BigDecimal side1 = new BigDecimal(l/3);
		BigDecimal side2 = new BigDecimal(l/3);
		BigDecimal side3 = new BigDecimal(l/3);
		System.out.println(side1.multiply(side2).multiply(side3));
	}
} Main public static void main(String[] args) {

		Scanner sc =new Scanner(System.in);
		double l=sc.nextDouble();
		BigDecimal side1 = new BigDecimal(l/3);
		BigDecimal side2 = new BigDecimal(l/3);
		BigDecimal side3 = new BigDecimal(l/3);
		System.out.println(side1.multiply(side2).multiply(side3));
	} main {

		Scanner sc =new Scanner(System.in);
		double l=sc.nextDouble();
		BigDecimal side1 = new BigDecimal(l/3);
		BigDecimal side2 = new BigDecimal(l/3);
		BigDecimal side3 = new BigDecimal(l/3);
		System.out.println(side1.multiply(side2).multiply(side3));
	} Scanner sc =new Scanner(System.in); sc new Scanner(System.in) double l=sc.nextDouble(); l sc.nextDouble() sc.nextDouble sc BigDecimal side1 = new BigDecimal(l/3); side1 new BigDecimal(l/3) BigDecimal side2 = new BigDecimal(l/3); side2 new BigDecimal(l/3) BigDecimal side3 = new BigDecimal(l/3); side3 new BigDecimal(l/3) System.out.println(side1.multiply(side2).multiply(side3)) System.out.println System.out System System.out side1.multiply(side2).multiply(side3) side1.multiply(side2).multiply side1.multiply(side2) side1.multiply side1 side2 side3 String[] args args public class Main {
	public static void main(String[] args) {

		Scanner sc =new Scanner(System.in);
		double l=sc.nextDouble();
		BigDecimal side1 = new BigDecimal(l/3);
		BigDecimal side2 = new BigDecimal(l/3);
		BigDecimal side3 = new BigDecimal(l/3);
		System.out.println(side1.multiply(side2).multiply(side3));
	}
} public class Main {
	public static void main(String[] args) {

		Scanner sc =new Scanner(System.in);
		double l=sc.nextDouble();
		BigDecimal side1 = new BigDecimal(l/3);
		BigDecimal side2 = new BigDecimal(l/3);
		BigDecimal side3 = new BigDecimal(l/3);
		System.out.println(side1.multiply(side2).multiply(side3));
	}
} Main
import java.math.BigDecimal;
import java.util.Scanner;

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

		Scanner sc =new Scanner(System.in);
		double l=sc.nextDouble();
		BigDecimal side1 = new BigDecimal(l/3);
		BigDecimal side2 = new BigDecimal(l/3);
		BigDecimal side3 = new BigDecimal(l/3);
		System.out.println(side1.multiply(side2).multiply(side3));
	}
}