import java.util.Scanner;

public class Main {
	void run(){
		Scanner s = new Scanner(System.in);
		int H = s.nextInt();
		int W = s.nextInt();
		for(int i = 0; i < H; i++){
			if(W == 1) System.out.println("#");
			for(int j = 0; j < W / 2 ; j++){
				
				if(i % 2 == 0){
					System.out.print("#.");
				}
				else{
					System.out.print(".#");
				}
			}
			System.out.println();
		}
	}
	public static void main(String[] args) {
		/* 
		 * Main x;
		 * x = new Main();
		 * x.run();
		 * ??¨????????????
		 */
		new Main().run();
		
	}
}