In a N x N grid composed of 1 x 1 squares, each 1 x 1 square consists of a /, , or blank space. These characters divide the square into contiguous regions.
(Note that backslash characters are escaped, so a \ is represented as "\".)
Return the number of regions.
Example 1:
Input:
[
" /",
"/ "
]
Output: 2
Explanation: The 2x2 grid is as follows:

Example 2:
Input:
[
" /",
" "
]
Output: 1
Explanation: The 2x2 grid is as follows:

Example 3:
Input:
[
"\\/",
"/\\"
]
Output: 4
Explanation: (Recall that because \ characters are escaped, "\\/" refers to \/, and "/\\" refers to /\.)
The 2x2 grid is as follows:

Example 4:
Input:
[
"/\\",
"\\/"
]
Output: 5
Explanation: (Recall that because \ characters are escaped, "/\\" refers to /\, and "\\/" refers to \/.)
The 2x2 grid is as follows:

Example 5:
Input:
[
"//",
"/ "
]
Output: 3
Explanation: The 2x2 grid is as follows:

Note:
- 1 <= grid.length == grid[0].length <= 30
- grid[i][j] is either '/', '', or ' '.