In this task your given a passage and a question in Catalan, you must answer the question based on the passage. The answer to the question can be extracted directly from the passage. The question will have a single correct answer. The answer will be a continuous span of text from the given passage. The correct answer will be short; it will not be more than a few words.

Passage: El llati hereta sis dels vuit casos gramaticals originals del protoindoeuropeu: el nominatiu, el vocatiu, l'acusatiu, el genitiu, el datiu i l'ablatiu. El cas locatiu indoeuropeu sobrevisque en les declinacions d'alguns toponims i substantius, com ara Roma 'Roma' (locatiu Romae) o domus 'casa' (locatiu domi). Algunes formes adverbials que acaben en -e son vestigis del cas instrumental.[1]
Question: Quants casos gramaticals del protoindoeuropeu va heretar el llati?
sis