HEXBOARD  Hexagonal Board
Square boards (as the chessboard) are really common among games and luckily, they are easy
to draw with the help of a ruler. However, there exist other games that requiere hexagonal
boards, that are much harder to draw by hand.
The Institute for Client Permanent Comfort (ICPC) of a famous board game factory has decided
to provide their customers with an automated program to build hexagonal boards for several
games. The size of an hexagonal board is determined by a single integer N that indicates how
many cells there are in each of the 6 sides of the board. For example, a board of size N = 2
should look as follows when drawn by the program.
_
_/ \_
/ \_/ \
\_/ \_/
/ \_/ \
\_/ \_/
\_/
Your task is to help ICPC in making the program.
Input
The input contains several test cases. Each test case is described in a single line that contains
an integer N representing the size of the board (1 ≤ N ≤ 20). The last line of the input
contains a single −1 and should not be processed as a test case.
Output
For each test case output the hexagonal board of the required size, and a line with exactly
three asterisks. You have to follow the sample input and output, as well as the example given
above. Use only regular spaces, underscores (“ ”), slashes (“/”) and backslashes (“\”). There
must be no trailing spaces at the end of printed lines, neither empty lines.
Example
Input: 1
3
1
Output: _
/ \
\_/
***
_
_/ \_
_/ \_/ \_
/ \_/ \_/ \
\_/ \_/ \_/
/ \_/ \_/ \
\_/ \_/ \_/
/ \_/ \_/ \
\_/ \_/ \_/
\_/ \_/
\_/
***
hide comments
Deepak Gupta:
20140924 09:34:37
MY wrong and correct submissions, both got AC. 

sarelfeniel:
20140421 01:49:05
Would make a fun code golf problem. 

Adhityaa:
20120320 05:14:25
N=2 example's first underscore i wrong... 

anon:
20100901 00:27:05
invalid F# checker ^_^ 
Added by:  Pablo Ariel Heiber 
Date:  20100819 
Time limit:  1.903s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: NODEJS OBJC PERL6 VB.NET 
Resource:  FCEyN UBA ICPC Selection 2008 