small edit in VBA Equation to calculate days off in work for the employees

Dear Sir,

Equation in "Ai" column
* It`s used to calculate days off in work for the employees
* Rest days for every employee in column A
* Equation calculates dayys on in work depending on cells more than "0"
* Equation excludes days in "AK" column


Required:
* The equation returns "0" value when excel calculates another sheet and returns "#VALUE!" error when excel calculates another workbook.

Find the attachment