Though not as dynamic as the previous year, Dallas offense remained incredibly efficient, led by Aikman, who finished the regular season completing 271 out of 392 passes for 3,100 yards, 15 touchdowns, and six interceptions. Smith recorded 1,486 rushing yards and nine touchdowns, while catching 57 passes for 414 yards and another touchdown, earning him his third consecutive NFL rushing title and the NFL Most Valuable Player Award.  Fullback Daryl Johnston was also a reliable backfield threat, scoring four touchdowns and contributing a career-high 50 receptions for 371 yards.  Pro Bowler Michael Irvin was once again the teams leading wide receiver, catching 88 passes for 1,330 yards and seven touchdowns.  Wide receiver Alvin Harper caught 36 passes for 777 yards and five touchdowns, while Pro Bowl tight end Jay Novacek had 44 receptions for 445 yards and one touchdown. Pro Bowlers Mark Stepnoski, Erik Williams, and Nate Newton anchored the offensive line.  On special teams, rookie receiver Kevin Williams (wide receiver) ranked seventh in the NFL with 381 yards on 36 punt returns, while also gaining 689 kickoff return yards and catching 20 passes for 151 yards.
Question: How many more touchdowns did Alvin Harper have than Jay Novacek?
Answer: 4