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

public class Main {

	public static void main(String[] args) throws Exception {

//    	File file = new File("test.txt");
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);
    	int L = sc.nextInt();
    	sc.close();
    	BigDecimal bd = BigDecimal.valueOf(L);
    	BigDecimal three = BigDecimal.valueOf(3);;
    	BigDecimal ans = bd.divide(three, 7, RoundingMode.HALF_UP);
    	System.out.println(ans.pow(3));
    }

} 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) throws Exception {

//    	File file = new File("test.txt");
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);
    	int L = sc.nextInt();
    	sc.close();
    	BigDecimal bd = BigDecimal.valueOf(L);
    	BigDecimal three = BigDecimal.valueOf(3);;
    	BigDecimal ans = bd.divide(three, 7, RoundingMode.HALF_UP);
    	System.out.println(ans.pow(3));
    }

} Main public static void main(String[] args) throws Exception {

//    	File file = new File("test.txt");
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);
    	int L = sc.nextInt();
    	sc.close();
    	BigDecimal bd = BigDecimal.valueOf(L);
    	BigDecimal three = BigDecimal.valueOf(3);;
    	BigDecimal ans = bd.divide(three, 7, RoundingMode.HALF_UP);
    	System.out.println(ans.pow(3));
    } main {

//    	File file = new File("test.txt");
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);
    	int L = sc.nextInt();
    	sc.close();
    	BigDecimal bd = BigDecimal.valueOf(L);
    	BigDecimal three = BigDecimal.valueOf(3);;
    	BigDecimal ans = bd.divide(three, 7, RoundingMode.HALF_UP);
    	System.out.println(ans.pow(3));
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int L = sc.nextInt(); L sc.nextInt() sc.nextInt sc sc.close() sc.close sc BigDecimal bd = BigDecimal.valueOf(L); bd BigDecimal.valueOf(L) BigDecimal.valueOf BigDecimal L BigDecimal three = BigDecimal.valueOf(3); three BigDecimal.valueOf(3) BigDecimal.valueOf BigDecimal 3 BigDecimal ans = bd.divide(three, 7, RoundingMode.HALF_UP); ans bd.divide(three, 7, RoundingMode.HALF_UP) bd.divide bd three 7 RoundingMode.HALF_UP RoundingMode RoundingMode.HALF_UP System.out.println(ans.pow(3)) System.out.println System.out System System.out ans.pow(3) ans.pow ans 3 String[] args args public class Main {

	public static void main(String[] args) throws Exception {

//    	File file = new File("test.txt");
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);
    	int L = sc.nextInt();
    	sc.close();
    	BigDecimal bd = BigDecimal.valueOf(L);
    	BigDecimal three = BigDecimal.valueOf(3);;
    	BigDecimal ans = bd.divide(three, 7, RoundingMode.HALF_UP);
    	System.out.println(ans.pow(3));
    }

} public class Main {

	public static void main(String[] args) throws Exception {

//    	File file = new File("test.txt");
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);
    	int L = sc.nextInt();
    	sc.close();
    	BigDecimal bd = BigDecimal.valueOf(L);
    	BigDecimal three = BigDecimal.valueOf(3);;
    	BigDecimal ans = bd.divide(three, 7, RoundingMode.HALF_UP);
    	System.out.println(ans.pow(3));
    }

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

public class Main {

	public static void main(String[] args) throws Exception {

//    	File file = new File("test.txt");
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);
    	int L = sc.nextInt();
    	sc.close();
    	BigDecimal bd = BigDecimal.valueOf(L);
    	BigDecimal three = BigDecimal.valueOf(3);;
    	BigDecimal ans = bd.divide(three, 7, RoundingMode.HALF_UP);
    	System.out.println(ans.pow(3));
    }

}