Y by
A positive integer is written on a blackboard. Carmela can perform the following operation as many times as she wants: replace the current integer
with another positive integer
, as long as
is a perfect square. For example, if the number on the blackboard is
, Carmela can replace it with
, because
, then replace it with
, because
. If the number on the blackboard is initially
, determine all integers that Carmela can write on the blackboard after finitely many operations.








