题解 | #空心正方形图案#

while True:
    try:
        n = int(input())
        for i in range(1,n+1):
            for j in range(1,n+1):
                if i == 1 or i == n:
                    print('* ', end=(''))
                elif j == 1 or j == n:
                    print('* ', end=(''))
                else:
                    print('  ', end=(''))
            print()
    except:
        break