Sand_Glass

using System;

class Program
{
    static void Main()
    {
        int N = int.Parse(Console.ReadLine());
        int nDot = 0;
        int nStar = 0;
        string row = null;
        int count = 1;

        for (int i = 0; i < N; i++)
        {
            if (i == 0 || i == N - 1)
            {
                row = new string('*', N);
                Console.WriteLine(row);
                continue;
            }

            if (i <= N / 2)
            {
                nDot = i;
                nStar = N / 2 - i;
                row = new string('.', nDot);
                row += new string('*', nStar);
                row += "*";
                row += new string('*', nStar);
                row += new string('.', nDot);
                Console.WriteLine(row);
            }
            else // print bottom part
            {
                nDot = N - i - 1;
                nStar = count;
                row = new string('.', nDot);
                row += new string('*', nStar);
                row += "*";
                row += new string('*', nStar);
                row += new string('.', nDot);
                Console.WriteLine(row);
                count++;
            }
        }
    }
}