Upvote:4
Policia Federal has the authority to reduce a visitor's stay to less than 90 days if they hold a visitor visa (Decree 9199/2017, Article 20). The situation is less clear for visa-exempted visitors, but it's safer to assume they also have the same authority. So I suggest you to consider you got 33 days and ask for extension if you want to stay more.
By the way, the extension procedure is not straightforward (see this question).