Problem Description

Lana loves drawing snowflakes. A snowflake of size $x$ is defined as follows:

• The center of the snowflake is a $\texttt{'+'}$.
• Above and below the $\texttt{'+'}$, there are $x$ $\texttt{'|'}$ characters.
• To the left and right of the $\texttt{'+'}$, there are $x$ $\texttt{'-'}$ characters.
• To the top-left and bottom-right of the $\texttt{'+'}$, there are $x$ $\texttt{'\textbackslash'}$ characters.
• To the bottom-left and top-right of the $\texttt{'+'}$, there are $x$ $\texttt{'/'}$ characters.

Snowflakes can overlap. Below are examples of snowflakes:

The three images show a snowflake of size $1$, two overlapping snowflakes of sizes $2$ and $1$, and a snowflake of size $1$ (incomplete as part of a snowflake of size $2$).

Given a character matrix of size $n \times m$, find the size of the largest snowflake within it.

Input Format

The first line contains two integers $n$ and $m$.

The next $n$ lines each contain a string of length $m$, representing an $n \times m$ matrix. The matrix is guaranteed to only contain the characters $\texttt{'+'}$, $\texttt{'-'}$, $\texttt{'|'}$, $\texttt{'/'}$, $\texttt{'\textbackslash'}$, and $\texttt{'.'}$.

Output Format

Output a single integer representing the size of the largest snowflake. If there are none, output $0$.

Sample Input and Output

Sample Input #1

5 6
\.\|/.
---+--
/./|\.
./.|.\
/..|..

Sample Output #1

1

Sample Input #2

7 7
\.|./..
.\|/...
--+--..
./|\...
/.|.\|/
....-+-
..../|\

Sample Output #2

2

Sample Input #3

7 7
\|/|\|/
-+-|-+-
/|\|/|\
---+---
\|/|\|/
-+-|-+-
/|\|/|\

Sample Output #3

1

Notes

Data Range

For all data, $1 \le n, m \le 50$.

见题面 Input 部分

见题面 Output 部分