import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    int a = scanner.nextInt();
    int b = scanner.nextInt();
    
    for (int i = 0; i < a; ++i) {
      for (int j = 0; j < b; ++j) {
        if ((i * b + j) % 2 == 0) System.out.print("#");
        else System.out.print(".");
      }
      System.out.println();
    }
  }
}
