Time Limit : sec, Memory Limit : KB

# Print a Chessboard

Draw a chessboard which has a height of H cm and a width of W cm. For example, the following figure shows a chessboard which has a height of 6 cm and a width of 10 cm.

#.#.#.#.#.
.#.#.#.#.#
#.#.#.#.#.
.#.#.#.#.#
#.#.#.#.#.
.#.#.#.#.#


Note that the top left corner should be drawn by '#'.

## Input

The input consists of multiple datasets. Each dataset consists of two integers H and W separated by a single space.

The input ends with two 0 (when both H and W are zero).

## Output

For each dataset, print the chessboard made of '#' and '.'.

Print a blank line after each dataset.

• 1 ≤ H ≤ 300
• 1 ≤ W ≤ 300

## Sample Input

3 4
5 6
3 3
2 2
1 1
0 0


## Sample Output

#.#.
.#.#
#.#.

#.#.#.
.#.#.#
#.#.#.
.#.#.#
#.#.#.

#.#
.#.
#.#

#.
.#

#