Диамант

using System;

namespace newPro
{
    class Program
    {
        static void Main(string[] args)
        {

            var n = int.Parse(Console.ReadLine());

            if (n == 1)
            {
                Console.WriteLine("*");
            }
            else if (n == 2)
            {
                Console.WriteLine("**");
            }
            else
            {
                int starsCount = 1;

                if (n % 2 == 0)
                {
                    starsCount = 2;
                }

                int dashesCount = (n - starsCount) / 2;

                string dashes = new string('-', dashesCount);
                string stars = new string('*', starsCount);

                Console.WriteLine("{0}{1}{0}", dashes, stars);


                for (int outerDashes = dashesCount - 1; outerDashes >= 0; outerDashes--)
                {
                    dashes = new string('-', outerDashes);

                    string inerDashes = new string('-', n - 2 * outerDashes - 2);

                    Console.WriteLine($"{dashes}*{inerDashes}*{dashes}");
                }

                for (int outerDashes = 1; outerDashes < (n - 1) / 2; outerDashes++)
                {
                    string outer = new string('-', outerDashes);

                    string inerDashes = new string('-', n - (2 * outerDashes) - 2);

                    Console.WriteLine($"{outer}*{inerDashes}*{outer}");
                }


                dashes = new string('-', dashesCount);

                Console.WriteLine("{0}{1}{0}", dashes, stars);
            }
        }
    }
}