Task: Question Answering
Input (English): Passage: Coming off their bye week, the Chargers went home for a Week 11 AFC West duel with the Denver Broncos on Monday night.  San Diego trailed early in the first quarter as Broncos running back Knowshon Moreno got a 4-yard touchdown run.  The Chargers answered with quarterback Philip Rivers finding wide receiver Malcolm Floyd on a 6-yard touchdown pass.  San Diego took the lead in the second quarter with a 1-yard touchdown run from fullback Mike Tolbert, followed by Rivers finding wide receiver Patrick Crayton on a 40-yard touchdown pass. The Chargers added onto their lead in the third quarter as Rivers connected with running back Darren Sproles on a 57-yard touchdown pass.  San Diego continued its dominating night with Rivers' 3-yard touchdown pass to fullback Jacob Hester.  Denver would close out the game with quarterback Kyle Orton completing a 13-yard touchdown pass to wide receiver Brandon Lloyd. 
Question: How many quarters did the Chargers keep the lead? 
Answer type: Number 
Output (English): 3.