Answer based on context:

The Browns traveled to Indianapolis to take on an Andrew Luck-led Colts offense. The Colts were able to score in the first quarter as Andrew Luck ran for a 3-yard touchdown making the score 7-0 for the only score of the game. The Browns responded in the 2nd quarter coming within a point when Brandon Weeden found Greg Little on a 14-yard pass (with a failed PAT) making the score 7-6. Then, Luck ran for another touchdown this time from 5 yards out to make the score 14-6 at halftime. The Browns came within a point again in the 3rd quarter as Weeden found Josh Gordon on a 33-yard pass making the score 14-13 but the Colts wrapped things up with Adam Vinatieri's 38-yard field goal followed by a scoreless 4th quarter making the final score 17-13 as the Browns' road record at this point of the season was 0-4 while their record overall was 1-6.

How many running touchdown yards did Luck have?
8