while True:
	(H, W)=[int(i)for i in input().split()]
	if H == W ==0:
		break

	for hc in range(H):
		for wc in range(W):
			if (hc + wc) % 2 ==0:
				print('#', end='')
			else:
				print(',', end='')
		print()
	print()