Counts the number of non-empty cells in a range of cells in the whole workbook.
COUNTA3D is very similar to the COUNTA function of Microsoft Excel. The main difference is that COUNTA3D considers all worksheets, while the original COUNTA function doesn't.
range_input - is the range from which you want to count the non-empty cells.
include_current - Optional. Boolean argument , either TRUE or FALSE. Decides whether the current worksheet is included in the function's consideration. TRUE means the current worksheet will be considered, and vice versa.