Pope Innocent VIII, in conflict with King Ferdinand I of Naples over Ferdinand's refusal to pay feudal dues to the papacy, excommunicated and deposed Ferdinand by a bull of 11 September 1489.  Innocent then offered the Kingdom of Naples to Charles VIII of France, who had a remote claim to its throne because his grandfather, Charles VII, King of France, had married Marie of Anjou  of the Angevin dynasty, the ruling family of Naples until 1442.  Innocent later settled his quarrel with Ferdinand and revoked the bans before dying in 1492, but the offer to Charles remained an apple of discord in Italian politics. Ferdinand died on January 25, 1494, and was succeeded by his son Alfonso II.
Question: How many years after the Angevin dynasty stopped fuling Naples did Innocent revoke the bans on Ferdinand?
Answer: 50