butterfly

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

            string topRowsLabel = "{0}\\ /{0}";
            int symbolCount = n - 2;

            for (int i = 0; i < symbolCount; i++)
            {
                string row = string.Empty;

                if (i % 2 == 0)
                {
                    row = string.Format(topRowsLabel, new string('*', symbolCount));
                }
                else
                {
                    row = string.Format(topRowsLabel, new string('-', symbolCount));
                }

                Console.WriteLine(row);
            }

            Console.WriteLine(new string(' ', n - 1) + "@");

            string botRowsLabel = "{0}/ \\{0}";

            for (int i = 0; i < symbolCount; i++)
            {
                string row = string.Empty;

                if (i % 2 == 0)
                {
                    row = string.Format(botRowsLabel, new string('*', symbolCount));
                }
                else
                {
                    row = string.Format(botRowsLabel, new string('-', symbolCount));
                }

                Console.WriteLine(row);
            }
        }