Hello

I have a spreadsheet with a blank column waiting to be populated by the user
- let's call it 'category A'.
At let's say every 5th cell going down the column I need an input box to pop
up and ask the user if any of the value he is inputting is 'category B'.
The value entered (even if it is a zero) should then be put in the cell
immediately to the right of the original cell.

Can anyone help please?