Answer based on context:

Hoping to rebound from their home loss to the Vikings, the Browns flew to Invesco Field at Mile High for a Week 2 duel with the Denver Broncos. After recovering a fumble on the opening kickoff, the Browns started with a short field but couldn't capitalize, settling for a 22-yard field goal by kicker Phil Dawson. Broncos quarterback Kyle Orton would complete a 2-yard touchdown pass to tight end Tony Scheffler for the game's first touchdown, and after a 47-yard field goal by Cleveland, the game was 7-6 after the first quarter. However, Cleveland's offensive struggles continued. Meanwhile, in the second and third quarter, kicker Matt Prater gave Denver a 23-yard and a 38-yard field goal. Afterwards, in the fourth quarter, the Broncos took control with touchdown runs by Peyton Hillis and Correll Buckhalter.

How many touchdown runs did the Broncos have in the fourth quarter?
2