Answer based on context:

After a tough home loss to the Texans, the Raiders traveled east to take on the Patriots.  The Raiders took an early lead when Sebastian Janikowski kicked a 49-yard field goal for a 3-0 game and the only score of the first quarter.  The Patriots took the lead in the 2nd quarter when Tom Brady found Rob Gronkowski on a 6-yard touchdown pass for a 7-3 game followed up by Stephen Gostowski kicking a 21-yard field goal for a 10-3 lead at halftime.  In the 3rd quarter, the Raiders went back to work as Janikowski nailed 2 field goals from 37 and 47 yards out coming within 4, 10-6 and then within 1, 10-9.  However, in the 4th quarter, the Patriots were able to eventually win the game when Gostkowski kicked 2 field goals from 20 and 36 yards out first for a 13-9 and the eventual final score of 16-9.  The Raiders were held without a touchdown in a single game for the first time since their 17-6 loss to the Panthers in 2012.

How many yards was the shortest field goal?
20