Answer based on context:

The Vikings traveled to Green Bay in week 12 to face a Packers team missing quarterback Aaron Rodgers, who had suffered a fractured left collarbone three weeks earlier. After successive punts from each side started the game, the Packers were the first to score as backup QB Scott Tolzien ran in for a 6-yard touchdown, but two field goals from Blair Walsh and a 1-yard touchdown run for Adrian Peterson meant the Vikings took a 13-7 lead into halftime. They extended their lead midway through the third quarter as Christian Ponder hit tight end Rhett Ellison for a 12-yard touchdown, and Walsh made it a 16-point lead with a 29-yard field goal on the second play of the fourth quarter. The Packers pulled the struggling Tolzien after the Ellison touchdown and replaced him with the recently re-signed Matt Flynn. Flynn then led the Packers on three consecutive scoring drives in the fourth quarter, starting with a 3-yard touchdown run for Eddie Lacy. Flynn's pass to Andrew Quarless on the two-point attempt fell incomplete, but Flynn was able to find Jarrett Boykin for a 6-yard touchdown on the next drive to reduce the Vikings' lead to three points. Inside the two-minute warning, Flynn combined with James Jones for a 28-yard completion on 4th-and-6, setting up Mason Crosby for the game-tying, 27-yard field goal. The Packers won the overtime coin toss and took the opening possession down to the Minnesota 2-yard line before having to settle for a field goal, only for Walsh to respond with a 35-yard effort. The two sides then exchanged possession as neither was able to put together a significant drive and the game ended in a 26-26 tie.

How many field goals were kicked in overtime?
2