Need formula to track seating availability.

Hello all,

It may be an easy fix but I am not yet that experienced in Excel. I am currently working with an organization who has provided me their seating charts which shows desks, cubes, offices etc.
It would be useful if I could somehow create a formula which would show the following:

When something is written in a cell showing the space is accounted for (name of person, employee number etc.) a number could be populated

x out of X seats available
x out of x cubes available etc.

Please let me know how i can go about doing this.

Thank you,

Greg