Brain Fart - Workflow Help - Search for Highest Num+1

[help1]

I need help creating a workflow. Any response would be greatly appreciated.
Items:
-Entrant
-Entrant’s Num (30 entrants, entrants should be labeled 1,2,3,4,5 etc to the #30)

I have a repeating group of 30 entrants. All entrants Number field is empty. I want to run a workflow on the 30 entrants that goes one entrant at a time and (searches entrants where number isn’t empty, sort by number descending) and save the current entrants number as the 1st items number +1.

In other words, I need all 30 entrants to have a number assigned and no two entrants can have the same number.

So far my workflow attempts is populating many entrants with the same number. So instead of 30 entrants having numbers 1-30, it is spitting out 30 entrants but 14 is the highest number.

[code-escapee]

Probably race conditions type of issue. Either space out the loop or better yet, run the workflow on a list of numbers (1-30) and a pass a entrant from the list in eavh workflow so you’ll ensure each entrant will get a number from 1 to 30