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 ' '.