Hourglass

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Axe
{
    class Axe
    {
        static void Main(string[] args)
        {
            var n = int.Parse(Console.ReadLine());
            var width = 2 * n + 1;
            var points = 2;

            Console.WriteLine(new string('*', width));
            Console.WriteLine(".*{0}*.", new string(' ', width - 4));

            for (int i = 1; i <= n - 2; i++)
            {
                Console.WriteLine("{0}*{1}*{0}"
              , new string('.', points)
              , new string('@', width - 4 - 2 * i)
              );
                points += 1;
            }

            Console.WriteLine("{0}*{1}"
                , new string('.', width / 2)
                , new string('.', width / 2));
            points -= 1;

            for (int i = n - 3; i >= 0; i--)
            {
                var whiteSpaces = (width - 2 * points - 3) / 2;
                Console.WriteLine("{0}*{1}@{1}*{0}"
             , new string('.', points)
             , new string(' ', whiteSpaces)
             , ('@')
             );
                points -= 1;
            }
            Console.WriteLine("{0}*{1}*{0}"
                ,('.')
                ,new string('@', width - 4));
            Console.WriteLine(new string('*', width));

        }
    }
}