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

public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		int l = scn.nextInt();
		float temp = (float) l / 3;
		BigDecimal b1 = new BigDecimal(temp);
		b1 = b1.multiply(new BigDecimal(temp));
		b1 = b1.multiply(new BigDecimal(temp));
		System.out.println(b1);
	}
} import java.math.BigDecimal; BigDecimal java.math import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		int l = scn.nextInt();
		float temp = (float) l / 3;
		BigDecimal b1 = new BigDecimal(temp);
		b1 = b1.multiply(new BigDecimal(temp));
		b1 = b1.multiply(new BigDecimal(temp));
		System.out.println(b1);
	}
} Main public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		int l = scn.nextInt();
		float temp = (float) l / 3;
		BigDecimal b1 = new BigDecimal(temp);
		b1 = b1.multiply(new BigDecimal(temp));
		b1 = b1.multiply(new BigDecimal(temp));
		System.out.println(b1);
	} main {
		Scanner scn = new Scanner(System.in);
		int l = scn.nextInt();
		float temp = (float) l / 3;
		BigDecimal b1 = new BigDecimal(temp);
		b1 = b1.multiply(new BigDecimal(temp));
		b1 = b1.multiply(new BigDecimal(temp));
		System.out.println(b1);
	} Scanner scn = new Scanner(System.in); scn new Scanner(System.in) int l = scn.nextInt(); l scn.nextInt() scn.nextInt scn float temp = (float) l / 3; temp (float) l / 3 (float) l 3 BigDecimal b1 = new BigDecimal(temp); b1 new BigDecimal(temp) b1 = b1.multiply(new BigDecimal(temp)) b1 b1.multiply(new BigDecimal(temp)) b1.multiply b1 new BigDecimal(temp) b1 = b1.multiply(new BigDecimal(temp)) b1 b1.multiply(new BigDecimal(temp)) b1.multiply b1 new BigDecimal(temp) System.out.println(b1) System.out.println System.out System System.out b1 String[] args args public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		int l = scn.nextInt();
		float temp = (float) l / 3;
		BigDecimal b1 = new BigDecimal(temp);
		b1 = b1.multiply(new BigDecimal(temp));
		b1 = b1.multiply(new BigDecimal(temp));
		System.out.println(b1);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		int l = scn.nextInt();
		float temp = (float) l / 3;
		BigDecimal b1 = new BigDecimal(temp);
		b1 = b1.multiply(new BigDecimal(temp));
		b1 = b1.multiply(new BigDecimal(temp));
		System.out.println(b1);
	}
} Main
import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		int l = scn.nextInt();
		float temp = (float) l / 3;
		BigDecimal b1 = new BigDecimal(temp);
		b1 = b1.multiply(new BigDecimal(temp));
		b1 = b1.multiply(new BigDecimal(temp));
		System.out.println(b1);
	}
}
