The Chiefs led for the first time all season in this game with a first-quarter touchdown which gave them the lead 7-0.  After relinquishing the lead, the Chiefs  tied the game at 13-13 at the end of regulation to force overtime.  However, despite the fact that they got the ball in overtime, QB Matt Cassel was picked off by Lamarr Woodley and the ball was returned to the Chiefs' 5-Yard line setting up the game-winning field goal for the Steelers as the Chiefs lost the game 16-13 and their record dropped to 1-8.
Question: How many points did the Chiefs lead by at the end of the first quarter?
Answer: 7