import java.io.*;
public class Main {
	public static void main(String[] args) throws IOException{
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String line = reader.readLine();
		String[] sarray = line.split(" ", -1);
		int H = Integer.parseInt(sarray[0]);
		int W = Integer.parseInt(sarray[1]);
		int n = 0;
		for(int i = 0; i < H; i++){
			if(i % 2 == 0){
				for(int j = 0; j < W; j++){
					if(j % 2 == 0){
						System.out.print("#");
					} else {
						System.out.print(".");
					}
				}
			} else {
				for(int j = 0; j < W; j++){
					if(j % 2 == 1){
						System.out.print("#");
					} else {
						System.out.print(".");
					}
				}
			}
		System.out.println();
		}
	}
}