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

namespace ConsoleApplication30
{
    class Program
    {
        static void Main(string[] args)
        {
            var ab = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int a = ab[0];
            int b = ab[1];
            {

                {
                    for (int c = 1; c <= a; c++)
                    {
                        if (a == 0 && b == 0)
                            break;
                        for (int d = 1; d <= b; d++)
                        {
                            if ((c + d) % 2 == 0)
                            {
                                Console.Write("#");
                            }
                            else
                            {
                                Console.Write(".");
                            }


                        }
                        Console.WriteLine();
                    }
                }
            }
        }
    }
}