The Steelers opened their 2016 season on the road against the Redskins. In the first quarter, the Redskins got on the board jumping out to a 6-0 lead with two field goals kicked by Dustin Hopkins from 31 and 40 yards out. In the second quarter it was all Steelers as they jumped out to leads of 7-6 and 14-6 at halftime when Ben Roethlisberger found Antonio Brown and Eli Rogers on 29-yard and 3-yard touchdown passes. After the break, the Steelers moved ahead 24-6 when Chris Boswell nailed a 46-yard field goal while Roethlisberger found Brown on a 26-yard touchdown pass. The Skins tried to rally later on in the quarter, but could only get away with a 34-yard field goal from Hopkins making the score 24-9. Though in the fourth quarter, they would eventually pull within 8 when Chris Thompson ran for a 1-yard touchdown making the score 24-16. Later on in the quarter, the Steelers sealed the game when DeAngelo Williams ran for two touchdowns from 15 and 6 yards out to make the final score 38-16.
Question: How many yards was the longest rushing touchdown?
Answer: 15