Is my visa / stamp, correct? (São Paulo)

I arrived in Brazil as a tourist a few days ago, I'm from UK so we get 90 days on arrival, but I just noticed my visa stamp has no final "exit date" on it.

Looking through my passport every other country I've ever been to the stamp / visa tell you when you have to leave the country by, as in the final date you can remain in the country.

Obviously I can count 90 days from arrival myself and make sure I don't stay any longer but it's useful to have it in writing so you know there can be no disagreement later with immigration.

Does Brazil not write / stamp the "final exit" date in it like other countries do?