P7956 [COCI 2014/2015 #6] METEOR

You need to restore a photo after a meteor has fallen. The photo before the meteor falls can be seen as an $R \times S$ character matrix. $\texttt X$ represents part of the meteor, $\texttt \#$ represents the ground, and the other parts are air, denoted by $\texttt .$. All $\texttt X$ cells are connected. Note that the meteor is strictly above the ground. That is, there exists a row of $\texttt .$ such that all $\texttt X$ are above it and all $\texttt \#$ are below it. The last row of the photo is guaranteed to be all $\texttt \#$. Please output the photo after the meteor lands. After landing, neither the meteor nor the ground changes its properties.

The first line contains two integers $R, S$. The next $R$ lines each contain a string of length $S$, describing the photo before the meteor falls.

Output an $R \times S$ matrix, representing the restored photo after the meteor falls.

#### Constraints For $100\%$ of the testdata, $3 \le R, S \le 3 \times 10^3$, and each character in the matrix is one of $\texttt{X \# .}$. #### Notes According to the original problem settings, the full score is 100 points. Translated from **[COCI 2014-2015](https://hsin.hr/coci/archive/2014_2015/)** [Contest #6](https://hsin.hr/coci/archive/2014_2015/contest6_tasks.pdf) Task C _**METEOR**_. Translated by ChatGPT 5