San Diego (4-7) led 13-3 with 7:51 remaining in the game before losing 16-13 in overtime to the Baltimore Ravens (9-2). The Ravens faced fourth-and-29 at their own 37 with 1:37 left when running back Ray Rice caught a pass one yard past the line of scrimmage. He ran to the 50-yard line, where he made three Chargers miss with a 90-degree cut to his left. Rice gained the 29 yards needed for a first down after escaping safety Eric Weddle, who received a concussion on the play as he was blocked by wide receiver Anquan Boldin. The Ravens kicked a 38-yard field goal to tie the game at the end of regulation, and made another 38-yarder to win with 1:07 left in overtime. Rivers threw a 21-yard touchdown to Floyd and Novak kicked two field goals for the Chargers' scores. Rivers was sacked six times, but did not have a turnover for only the third time in 11 games; he entered the contest with 14 interceptions and four lost fumbles. The Ravens' fourth-and-29 was the longest fourth-down conversion in the NFL since 2001. It was the third time the Chargers blew a double-digit lead in the second half, including the earlier back-to-back losses to the Saints and Broncos. After being 8-0 under Turner in November from 2009-2010, San Diego fell to 1-7, the second-worst November record in the league since 2011.
Question: How many unanswered points did the Ravens score to overcome a fourth quarter deficit to the Chargers?
Answer: 13