context:  Coming off their road win against the Ravens, the Colts flew to Reliant Stadium for an AFC South showdown with the Texans, their second meeting of the season. Houston dominated throughout the first half, scoring 17 points. The Colts took over from there, scoring 35 points, one of which was an interception returned 27 yards by Clint Session. With the win, the Colts went to 11-0and their winning streak improved to 19 games. Also, with the win and Jacksonville's loss to San Francisco, the Colts clinched the AFC South division title, the first team to clinch a playoff berth this season.
question: How many points did the Colts win by?
answer: 18