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ZOJ Problem Set - 2423
Fractal

Time Limit: 2 Seconds      Memory Limit: 65536 KB

A fractal is an object or quantity that displays self-similarity, in a somewhat technical sense, on all scales. The object need not exhibit exactly the same structure at all scales, but the same "type" of structures must appear on all scales.

A box fractal is defined as below :

  • A box fractal of degree 1 is simply
    X
    
  • A box fractal of degree 2 is
    X X
     X
    X X
    
  • If using B(n - 1) to represent the box fractal of degree n - 1, then a box fractal of degree n is defined recursively as following
    B(n - 1)          B(n - 1)
             B(n - 1)
    B(n - 1)          B(n - 1)
    

Your task is to draw a box fractal of degree n.


Input

The input consists of several test cases. Each line of the input contains a positive integer n which is no greater than 7. The last line of input is a negative integer -1 indicating the end of input.


Output

For each test case, output the box fractal using the 'X' notation. Please notice that 'X' is an uppercase letter. Print a line with only a single dash after each test case. Don't output any trailing spaces at the end of each line, or you may get an 'Presentation Error'!


Sample Input

1
2
3
4
-1

Sample Output

X
-
X X
 X
X X
-
X X   X X
 X     X
X X   X X
   X X
    X
   X X
X X   X X
 X     X
X X   X X
-
X X   X X          X X   X X
 X     X            X     X
X X   X X          X X   X X
   X X                X X
    X                  X
   X X                X X
X X   X X          X X   X X
 X     X            X     X
X X   X X          X X   X X
         X X   X X
          X     X
         X X   X X
            X X
             X
            X X
         X X   X X
          X     X
         X X   X X
X X   X X          X X   X X
 X     X            X     X
X X   X X          X X   X X
   X X                X X
    X                  X
   X X                X X
X X   X X          X X   X X
 X     X            X     X
X X   X X          X X   X X
-

Source: Asia 2004, Shanghai (Mainland China), Preliminary
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