PROGRAMMING:Beautiful spiral
Output a square matrix with specified side length, and the values in the matrix are spirally distributed from the middle.
###Input format:
The input line contains an integer n (2 < = n < = 20, and N is even).
###Output format:
Matrices of length and width n
###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 line contains an integer n (2 < = n < = 20, and N is even).
###Output format:
Matrices of length and width n
###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