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 j==1 or i==n or j==n:
                    print("* ",end="")
                else:
                    print("  ",end="")
            print()
    except:
        break