Spirals

Your task is to write a program that prints “spirals” of size $n \times n$, as it is shown in the examples.

Input

The input consists of a sequence of natural numbers ended with zero.

Output

For each $n$, your program must print a spiral of size $n \times n$. Notice that in the row of the bottom and the column on the rigth there only are |’X’|s. Print a line in white after each spiral.

Observation

Although it is not essential use a matrix to solve this problem, do it for simplicity.

Author

Salvador Roura (en: Carlos Molina)

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