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

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int L = sc.nextInt();
		
		BigDecimal bd1 = BigDecimal.valueOf(L*L*L);
		BigDecimal bd2 = new BigDecimal(27);
		
		BigDecimal bd3 = bd1.divide(bd2,10, RoundingMode.HALF_UP);

		
		System.out.println(bd3);
	}
} 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 sc = new Scanner(System.in);
		int L = sc.nextInt();
		
		BigDecimal bd1 = BigDecimal.valueOf(L*L*L);
		BigDecimal bd2 = new BigDecimal(27);
		
		BigDecimal bd3 = bd1.divide(bd2,10, RoundingMode.HALF_UP);

		
		System.out.println(bd3);
	}
} Main public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int L = sc.nextInt();
		
		BigDecimal bd1 = BigDecimal.valueOf(L*L*L);
		BigDecimal bd2 = new BigDecimal(27);
		
		BigDecimal bd3 = bd1.divide(bd2,10, RoundingMode.HALF_UP);

		
		System.out.println(bd3);
	} main {

		Scanner sc = new Scanner(System.in);
		int L = sc.nextInt();
		
		BigDecimal bd1 = BigDecimal.valueOf(L*L*L);
		BigDecimal bd2 = new BigDecimal(27);
		
		BigDecimal bd3 = bd1.divide(bd2,10, RoundingMode.HALF_UP);

		
		System.out.println(bd3);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int L = sc.nextInt(); L sc.nextInt() sc.nextInt sc BigDecimal bd1 = BigDecimal.valueOf(L*L*L); bd1 BigDecimal.valueOf(L*L*L) BigDecimal.valueOf BigDecimal L*L*L L*L*L L L L BigDecimal bd2 = new BigDecimal(27); bd2 new BigDecimal(27) BigDecimal bd3 = bd1.divide(bd2,10, RoundingMode.HALF_UP); bd3 bd1.divide(bd2,10, RoundingMode.HALF_UP) bd1.divide bd1 bd2 10 RoundingMode.HALF_UP RoundingMode RoundingMode.HALF_UP System.out.println(bd3) System.out.println System.out System System.out bd3 String[] args args public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int L = sc.nextInt();
		
		BigDecimal bd1 = BigDecimal.valueOf(L*L*L);
		BigDecimal bd2 = new BigDecimal(27);
		
		BigDecimal bd3 = bd1.divide(bd2,10, RoundingMode.HALF_UP);

		
		System.out.println(bd3);
	}
} public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int L = sc.nextInt();
		
		BigDecimal bd1 = BigDecimal.valueOf(L*L*L);
		BigDecimal bd2 = new BigDecimal(27);
		
		BigDecimal bd3 = bd1.divide(bd2,10, RoundingMode.HALF_UP);

		
		System.out.println(bd3);
	}
} Main
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int L = sc.nextInt();
		
		BigDecimal bd1 = BigDecimal.valueOf(L*L*L);
		BigDecimal bd2 = new BigDecimal(27);
		
		BigDecimal bd3 = bd1.divide(bd2,10, RoundingMode.HALF_UP);

		
		System.out.println(bd3);
	}
}