Total course time (based on slide timelines)

Happy New Year everyone,

I have a large (~130) slide course and would like to determine the approximate time length it would take a student to run through the slides. I am not concerned with the time it will take the student to read and answer questions, just the running time (timing line is playing).  I don't look forward to sitting there with a stopwatch running through the entire course, or adding up the length of each slide's timeline. 

I am aware of the built-in variable ProjectElapsedTime, which I could insert and then run the entire course (instead of using a stopwatch), but I'd rather not have to spend hours clicking NEXT.

Anyone have any clues?

Thanks and cheers, Russ