Page numbers missing

I'm creating a project by importing a PowerPoint. The PowerPoint slides are numbered; however, when I import them into Storyline the number are wiped out. I do not see a way to add numbering in Storyline.

So far, the only way I've found to get around this problem is to add a text box with the slide number to each slide in the PowerPoint (i.e., hand-number it instead of using the automatic numbering). This is time-consuming and inefficient and creates problems if I need to change the order of slides in the presentation.

There must be a better way to handle this problem. Can you suggest an alternative?

Thanks!