Answer based on context:

For their last home game of the regular season, the Lions hosted a rare Saturday evening contest against the San Diego Chargers. The first half was all Detroit. First came a 7-yard touchdown pass from Matthew Stafford to Brandon Pettigrew, followed by a 30-yard field goal by Jason Hanson. In the second quarter, Kevin Smith caught a 3-yard touchdown pass, followed by a Calvin Johnson 14-yard touchdown catch in the final minute of the half, putting the Lions up 24-0 at the break. After the intermission, the Chargers finally got on the board with an 11-yard touchdown pass from Philip Rivers to Malcolm Floyd, followed by a 22-yard field goal by Nick Novak. Detroit responded with a 6-yard touchdown run by Kevin Smith. The only points of the fourth quarter came when Cliff Avril intercepted a pass from Philip Rivers and ran it in 4 yards for a touchdown. With the win, the Lions improved to 10-5 and clinched an NFC Wildcard spot in the playoffs, their first postseason appearance since 1999.  Also, the Lions became the only NFC North team to beat all AFC West teams on the season.

How many touchdowns were scored?
6