Trapezoid

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

namespace Trapezoid
{
    class Trapezoid
    {
        static void Main()
        {
            //Input
            int N = int.Parse(Console.ReadLine());
            int rows = N + 1;
            int cols = 2 * N;
            int[,] matrix = new int[rows, cols];

            //Fill the matrix
            for (int col = N; col < cols; col++)
            {
                matrix[0, col] = 1;
            }

            for (int row = 1; row < rows; row++)
            {
                matrix[row, cols - 1] = 1;
            }

            for (int col = cols - 1; col >= 0; col--)
            {
                matrix[rows - 1, col] = 1;
            }

            //int currentRow = 0;
            int currentCol = 0;
            for (int row = rows - 1; row >= 0; row--)
            {
                matrix[row, currentCol] = 1;
                currentCol++;
            }

            //Output
            for (int row = 0; row < rows; row++)
            {
                for (int col = 0; col < cols; col++)
                {
                    if (matrix[row, col] == 0)
                    {
                        Console.Write(".");
                    }
                    else if (matrix[row, col] == 1)
                    {
                        Console.Write("*");
                    }
                }
                Console.WriteLine();
            }
        }
    }
}