Coming off their home win over the Eagles, the Ravens flew to Paul Brown Stadium for a Week 13 AFC North rematch with the Cincinnati Bengals.  In the first quarter, Baltimore scored first with a 27-yard field goal by kicker Matt Stover.  In the second quarter, the Ravens increased their lead as Stover made a 21-yard field goal, while rookie quarterback Joe Flacco completed a 4-yard TD pass to TE Todd Heap.  The Bengals would close out the half as kicker Shayne Graham nailed a 21-yard field goal. In the third quarter, Baltimore pulled away as WR Mark Clayton (on a trick play) threw a 32-yard TD pass to WR Derrick Mason and caught a 70-yard TD pass from Flacco.  In the fourth quarter, the Ravens sealed the victory as safety Jim Leonhard returned an interception 35 yards for a touchdown. With the win, not only did Baltimore improve to 8-4, but they swept the season series from Cincinnati for the first time since 2002.
Question: How many more touchdowns were scored in the second half, compared to the first half?
Answer: 2