In week 4, the Lions flew to The Windy City for a NFC North duel with the Chicago Bears. Detroit threw the opening punch in the first quarter with running back Kevin Smith's 1-yard touchdown run. The Bears would respond with quarterback Jay Cutler's 5-yard touchdown run, yet Detroit answered with rookie quarterback Matthew Stafford completing a 14-yard touchdown pass to tight end Will Heller.  Chicago took the lead in the second quarter with Cutler's 2-yard touchdown pass to tight end Kellen Davis and a 1-yard touchdown pass to tight end Greg Olsen, but the Lions would tie the game prior to halftime with Smith's 3-yard touchdown run, capping off a 98-yard drive. However, in the third quarter, the Bears would set the tempo for the second half.  It immediately began with wide receiver Johnny Knox returning the half's opening kickoff 102 yards for a touchdown, followed by a 52-yard and a 22-yard field goal from kicker Robbie Gould.  Detroit tried to rally in the fourth quarter with kicker Jason Hanson's 35-yard field goal, but Chicago pulled away with running back Matt Fort&#233;'s 37-yard touchdown run and running back Garrett Wolfe's 2-yard touchdown run. Stafford (24-of-36, 296 yards, TD, INT) left the game during the fourth quarter with a knee injury.With the loss, the Lions fell to 1-3.
Question: How many of Stafford's passes were incomplete?
Answer: 12