Answer based on context:

Returning to Candlestick Park, the 49ers geared up for a rematch against Brett Favre and his new team.  The game started when the 49ers attempted an onside kick, recovered by the Jets.  Later, the 49ers went up first as Shaun Hill completed a pass to Jason Hill that was fumbled at the goal line and recovered by offensive tackle Joe Staley for the touchdown.  Then, Brett Favre ran for a 2-yard touchdown.  The 49ers retook the lead as Shaun Hill completed a touchdown screen pass to Frank Gore.  After half-time, Thomas Jones plowed through the 49ers secondary to get a 17-yard score. On the ensuing 49ers possession, a Shaun Hill touchdown pass to Delanie Walker was called back, and the 49ers settled for a Joe Nedney 32-yard field goal.  In the fourth quarter, the 49ers cemented their lead when Shaun Hill completed a 3-yard touchdown pass to a diving Bryant Johnson.  The Jets had enough time to make a late comeback, but a Brett Favre deep pass was intercepted by Walt Harris.  The 49ers ran down the clock and punted, and the Jets did not have sufficient time to attempt the comeback. The 49ers fumbled the ball a total of 5 times, although, fortunately for them, only one was lost. With the win, the 49ers improved to 5-8. However, they were officially eliminated from playoff contention with the Arizona Cardinals win against the St. Louis Rams, clinching the NFC West for Arizona.

How many fumbles did the 49ers have?
5