is pretty clear: "No person shall be elected to the office of the President more than twice..." You cannot be President for two terms and then be President again later. That President cannot even be Vice President, by virtue of the
, so unless it is repealed, two is as far as
you can get. The only exception to this whole scheme is when a person assumes the Presidency after the half-way mark in a term. The President would have served out one term, could be elected to a second term, and is still eligible for one more full term.