The Colts began their season on the road against the Bears.  The game was highly hyped due to the start of the career of rookie QB Andrew Luck.  The Colts drew first blood in the first quarter as Jerrell Freeman returned an interception 3 yards for a touchdown and a 7-0 lead.  However, the Bears tied the game with Michael Bush's 1-yard run to tie the game at 7-7.  In the 2nd quarter, the Bears took the lead as Brandon Marshall caught a 3-yard touchdown pass from Jay Cutler to make the score 14-7.  They then increased their lead when Robbie Gould scored a 35-yard field goal to make the score 17-7.  The Colts drew closer to shorten the lead to 3 with Donald Brown's 18-yard touchdown run to make the score 17-14.  However, with just seconds before halftime, the Bears drove down the field while Michael Bush ran in on a 1-yard touchdown for a 24-14 halftime lead.  In the 3rd quarter the Bears gained momentum once more with Matt Forte's 6-yard touchdown run for a 31-14 lead and then Robbie Gould's 26-yard field goal for a 34-14 lead.  In the fourth quarter, Luck threw his first touchdown pass of the regular season.  A 4-yard pass to Donnie Avery to shorten the lead to 34-21.  However, the Bears capitalized the victory with Cutler's 42-yard pass to Alshon Jeffery for a final score of 41-21.
Question: How many 1-yard touchdown runs did Michael Bush have in the first half?
Answer: 2