In week 15, the Lions traveled west for an interconference duel with the Oakland Raiders. The Raiders struck first when Louis Murphy ran in a touchdown from 12 yards out. The Lions responded with a 51-yard touchdown pass from Matthew Stafford to Calvin Johnson. In the second quarter, Oakland re-took the lead when Darrius Heyward-Bey caught a 43-yard pass from Carson Palmer, but the Lions tied it back up when Nate Burlseon caught a 39-yard pass for a TD. Oakland took the lead back just before halftime with a 46-yard field goal by Sebastian Janikowski. After a scoreless third quarter, the Raiders kicked a 51-yard field goal, and added 7 more points when Aaron Curry picked up a Matthew Stafford fumble and ran it in 6 yards for a touchdown, putting them up 27-14 with just under 8 minutes left in the game. The Lions then mounted their 6th comeback of the season from a 13+ point deficit, first with a 3-yard catch by Titus Young, then Calvin Johnson caught his second touchdown of the game from 6 yards out to put them up 28-27 with 39 seconds left to play. The Raiders then drove down the field, and attempted a 65-yard field goal on fourth down, which would have broken Sebastian Janikowski's own NFL-record of 63 yards which he shares with two other placekickers, but it was blocked by Ndamukong Suh, giving the Lions the win and keeping their playoff hopes alive as the team improved to 9-5, securing their first winning season since 2000.
Question: How many touchdowns did Johnson have?
Answer: 2