Spirals P44243

Write a program that prints “spirals” of size n × n, as it is shown in the examples.

Input

Input consists of a sequence of strictly positive natural numbers, ended with zero.

Output

For each n, print a spiral of size n × n. Note that in the bottom row and in the right column there are only ‘X’s. Print an empty line after each spiral.

Observation

A matrix is not needed to solve this problem, but use it for simplicity.