CF510A.Fox And Snake

Fox Ciel starts to learn programming. The first task is drawing a fox! However, that turns out to be too hard for a beginner, so she decides to draw a snake instead.

A snake is a pattern on a n by m table. Denote c-th cell of r-th row as (r, c). The tail of the snake is located at (1, 1), then it's body extends to (1, m), then goes down 2 rows to (3, m), then goes left to (3, 1) and so on.

Your task is to draw this snake for Fox Ciel: the empty cells should be represented as dot characters ('.') and the snake cells should be filled with number signs ('#').

Consider sample tests in order to understand the snake pattern.

小狐狸 Ciel 开始学习编程。第一个任务是画一只狐狸！然而，这对初学者来说太难了，因此她决定改画一条蛇。

蛇是一种位于 $n$ 行 $m$ 列表格上的图案。记第 $r$ 行第 $c$ 列的格子为 $(r,\,c)$。蛇的尾部位于 $(1,\,1)$，其身体向右延伸至 $(1,\,m)$，然后向下移动 2 行到达 $(3,\,m)$，再向左延伸至 $(3,\,1)$，依此类推。

你的任务是为小狐狸 Ciel 画出这条蛇：空单元格用英文句点字符（'.'）表示，蛇所占据的单元格则用井号字符（'#'）填充。

请参考样例测试以理解蛇的图案。

The only line contains two integers: n and m (3 ≤ n, m ≤ 50).

n is an odd number.

唯一一行包含两个整数：$n$ 和 $m$（$3 \leq n, m \leq 50$）。

$n$ 是一个奇数。

Output n lines. Each line should contain a string consisting of m characters. Do not output spaces.

输出 n 行。每行应包含一个由 m 个字符组成的字符串。不要输出空格。