Be sure that you receive an
entry/departure card at Immigration when you arrive in Brazil.
This document will be required when you leave the country.
You may end up receiving and filling out an
additional card upon departure. You will therefore need to
keep a hold of it to show the next time you arrive in Brazil.
In any case, keep this card with your
passport at all times. You may be fined for failure to
turn in the card when required.