Structured Program I - Print a Chessboard

Time Limit : 1 sec, Memory Limit : 131072 KB
Japanese version is here

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.

Constraints

1 ≤ H, W ≤ 300

Sample Input

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

Sample Output

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

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

#.#
.#.
#.#

#.
.#

#