P11752 [COCI 2024/2025 #5] Zid
Background
译自 [COCI 2024/2025 #5](https://hsin.hr/coci/) T2。$\texttt{1s,0.5G}$。满分为 $70$。
Description
Mr. Malnar wants to put up a picture of himself on the wall. The wall can be
represented as a matrix with $n$ rows and $m$ columns. Since he has placed his
picture on the wall many times before, some positions still have nails embedded
in them. Such positions are marked with the symbol "$\texttt{\#}$", while empty spots are
marked with the symbol "$\texttt{.}$".
The picture has a rectangular shape with arbitrary dimensions and is placed on
the wall in a way that it covers a rectangular area. The picture can be placed on
the wall if it covers at most one position that contains a nail.
Help Mr. Malnar calculate the number of ways he can place his picture on the wall.
Input Format
N/A
Output Format
N/A
Explanation/Hint
**Clarification of the first example:**
Each placement of the picture is valid as long as it covers at most one nail.
**Clarification of the second example:**
The picture cannot be placed in a way that it covers positions $(3, 1)$ and $(4, 1)$ simultaneously.
### Scoring
| Subtask | Points | Constraints |
| :--: | :--: | :--: |
| $1$ | $17$ | $n,m ≤ 10$ |
| $2$ | $21$ | $n,m ≤ 100$ |
| $3$ | $32$ | No additional constraints. |