Square Frame

using System;

namespace SquareFrame
{
    class SquareFrame
    {
        static void Main()
        {
            var n = int.Parse(Console.ReadLine());

            if (n > 2)
            {


                for (int i = 1; i <= 1; i++)
                {
                    Console.Write("+" + " " + "-");
                    for (int k = 1; k < n - 2; k++)
                    {
                        Console.Write(" " + "-");
                    }
                    Console.WriteLine(" " + "+");
                }

                for (int i = 1; i <= n - 2; i++)
                {
                    Console.Write("|" + " " + "-");
                    for (int k = 1; k < n - 2; k++)
                    {
                        Console.Write(" " + "-");
                    }
                    Console.WriteLine(" " + "|");
                }

                for (int i = 1; i <= 1; i++)
                {
                    Console.Write("+" + " " + "-");
                    for (int k = 1; k < n - 2; k++)
                    {
                        Console.Write(" " + "-");
                    }
                    Console.WriteLine(" " + "+");
                }
            }
            else if (n == 2)
            {
                Console.WriteLine("+" + " " + "+");
            }
        }
    }
}