The Titans opened the regular season at home against the New York Jets on September 10.  After a scoreless first quarter, the Titans started to seriously trail as opposing RB Kevan Barlow scored on a one-yard TD run (extra point attempt was good) and an 8-yard TD pass to opposing WR Jerricho Cotchery (extra point attempt failed).  In the third quarter, things didn't get any better, as opposing kicker Mike Nugent kicked an 18-yard field goal to make Tennessee trail 16-0.  In the fourth quarter, the Titans made a valiant attempt to come back, as RB Travis Henry got a 3-yard and a 1-yard TD run, which were both followed by successful two-point conversions.  However, the Jets were just too much as opposing TE Chris Baker caught a 12-yard TD to put the game away.  With the loss, the Titans began their season 0-1.
Question: How many more total yards were gained on passing touchdowns compared to rushing touchdowns?
Answer: 15