CF1669G.Fall Down

There is a grid with $n$ rows and $m$ columns, and three types of cells:

• An empty cell, denoted with '.'.
• A stone, denoted with '*'.
• An obstacle, denoted with the lowercase Latin letter 'o'.

All stones fall down until they meet the floor (the bottom row), an obstacle, or other stone which is already immovable. (In other words, all the stones just fall down as long as they can fall.)

Simulate the process. What does the resulting grid look like?

有一个 $n$ 行 $m$ 列的网格，包含三种类型的格子：

• 空格子，用 . 表示；
• 石头，用 * 表示；
• 障碍物，用小写拉丁字母 o 表示。

所有石头均向下掉落，直到碰到地板（最底行）、障碍物，或另一个已固定的石头为止。（换言之，所有石头尽可能地自由下落。）

请模拟该过程。最终的网格是什么样子？

The input consists of multiple test cases. The first line contains an integer $t$ ($1 \leq t \leq 100$) — the number of test cases. The description of the test cases follows.

The first line of each test case contains two integers $n$ and $m$ ($1 \leq n, m \leq 50$) — the number of rows and the number of columns in the grid, respectively.

Then $n$ lines follow, each containing $m$ characters. Each of these characters is either '.', '*', or 'o' — an empty cell, a stone, or an obstacle, respectively.

输入包含多个测试用例。第一行包含一个整数 $t$（$1 \leq t \leq 100$），表示测试用例的数量。随后是各测试用例的描述。

每个测试用例的第一行包含两个整数 $n$ 和 $m$（$1 \leq n, m \leq 50$），分别表示网格的行数和列数。

接下来是 $n$ 行，每行包含 $m$ 个字符。这些字符中每个均为 '.'、'*' 或 'o'，分别表示空单元格、石头或障碍物。

For each test case, output a grid with $n$ rows and $m$ columns, showing the result of the process.

You don't need to output a new line after each test, it is in the samples just for clarity.

对于每个测试用例，输出一个具有 $n$ 行和 $m$ 列的网格，展示该过程的结果。

无需在每个测试用例后输出空行，样例中仅为了清晰起见而添加了空行。