import java.io.*;

public class Main
{
	public static void main(String[] args)throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] str = br.readLine().split(" ");
		int H = Integer.parseInt(str[0]);
		int W = Integer.parseInt(str[1]);
		char a = '#';
		int c = 1;	
		for(int i = 1; i<=H; i++)
		{
			for(int j = 1; j<=W; j++)
			{
				System.out.print(a);
				if(j==W)	break;
				c = c * (-1);
				if(c==-1)		a = '.';
				else if(c==1)	a = '#';
			}
			System.out.println();
		}
		
	}
}