PROGRAMMING:Spiral matrix
This problem requires from the lower right corner to print the digital matrix according to the spiral descending.
###Input format:
The input is a positive integer n (1 = < n < = 20).
###Output format:
Spiral descending order output n rows n columns of digital matrix, each number occupies 4 width, left aligned.
###Input example:
```in
four
```
###Output example:
```out
10 9 8 7
11 2 1 6
12 3 4 5
13 14 15 16
```
answer：If there is no answer, please comment
###Input format:
The input is a positive integer n (1 = < n < = 20).
###Output format:
Spiral descending order output n rows n columns of digital matrix, each number occupies 4 width, left aligned.
###Input example:
```in
four
```
###Output example:
```out
10 9 8 7
11 2 1 6
12 3 4 5
13 14 15 16
```
answer：If there is no answer, please comment