How can we implement incremental naming system?

Just like how Mac or Windows gives incremental names to the new folder, how can we implement such system in database?

Let's say I have currently 3 folders(default names) i.e., untitled folder, untitled folder 2, untitled folder 3.
Now if I deletes untitled folder 2 and try to create new folder again Mac will name the new folder as untitled folder 2.

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