@Angelo **********
I think answering to the topicstarter is useless until is clear what is meant. Good question!
If he really has a visa, which I doubt, I guess he would already have known the difference between single entry and multi entry. For tjhe multi entry there is no limit, and the single entry is one time and then you need to apply again.
And the visa exempt works as long as IO believes you are tourist, that can even be zero times if there is suspicion you are no tourist for whatever reason.