The Steelers played their first home game of the year against the division rival Bengals in a rematch of the 2015 AFC Wild Card game. In the first quarter, the Steelers struck first when Ben Roethlisberger found Xavier Grimble on a 20-yard touchdown pass for a 7-0 lead. The Bengals came within 4 later on in the quarter when Mike Nugent kicked a 25-yard field goal for a 7-3 game. In the second quarter, the Steelers increased their lead when Chris Boswell kicked a 49-yard field goal to make it 10-3. The Bengals came within 4 again when Nugent kicked a 33-yard field goal to make it 10-6 at halftime. In the third quarter, the Steelers moved ahead by double digits when Roethlisberger found Jesse James on a 9-yard touchdown pass to make it 17-6. The Bengals reduced the lead when Nugent kicked another field goal from 21 yards out to make it 17-9. In the fourth quarter, the Steelers pulled away as Roethlisberger found De'Angelo Williams on a 4-yard touchdown pass to make it 24-9. Though the Bengals wrapped up the scoring of the game when Andy Dalton found Giovani Bernard on a 25-yard touchdown pass to make the final score 24-16. With the win, the Steelers started 2-0 for the first time since 2010.
Question: How many points were the Steelers leading by at halftime?
Answer: 4