automatically highlighting numbers 0 and 1

Lets say column A has a number of bought items and column B has the number of sold items. Column C is an equation (=A+-B) to show the current inventory. I need column C to automatically highlight when the number is either 1 or 0

.. any help?

Select the cells of interest, do Format > Conditional Formatting, Cell value is ... between ... 0 and 1, and set the highlighting as you wish.