Empty Square with *

using System;

class Program
{
    static void Main(string[] args)
    {
        int n = int.Parse(Console.ReadLine());
        Console.WriteLine(new string('*',n));
        for(int i=0;i<n-2;i++)
        {
            Console.Write("*");
            Console.Write(new string(' ',n-2));
            Console.WriteLine("*");
        }
        Console.WriteLine(new string('*', n));
    }
}