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