Coming off their Sunday night win over the Chiefs, the Steelers went home for a Week 13 AFC North rematch with the Cincinnati Bengals. In the first quarter, Cincinnati threatened to score after Bengals wide receiver AJ Green caught a 43-yard pass from quarterback Andy Dalton. Tight end Jermaine Gresham appeared to catch a 7-yard touchdown pass from Dalton, but it was nullified because of a false start penalty on Green. The Bengals lined up for a field goal, but could not get the kick off in time, causing a delay of game. After the five-yard penalty, the Bengals lined up for the field goal again. But this time, Pittsburgh's Cameron Heyward blocked the field goal, giving the Steelers the ball around the 20-yard line. Pittsburgh could not capitalize however, and punted it away. The rest of the 1st quarter was scoreless. Then in the 2nd quarter, the Steelers began a scoring frenzy. The first of Pittsburgh's 4 touchdowns came when Rashard Mendenhall ran in a score from 3 yards out to give Pittsburgh a 7-0 lead. He scored again on the Steelers' next drive, this time from 5 yards out. Pittsburgh scored yet again on their following drive when Ben Roethlisberger threw a 12-yard touchdown pass to Mike Wallace. Down 21-0, the Bengals finally got into the end zone. After a long drive going 80 yards, Dalton threw an 11-yard touchdown pass to Green. Though the Bengals brought the game to within 21-7, the Steelers would not let up. Pittsburgh answered Cincinnati with a 60-yard punt return by Antonio Brown, This gave the Steelers a 28-7 lead going into halftime. In the 3rd Quarter, Pittsburgh scored one more time when Roethlisberger threw a 19-yard touchdown pass to Wallace. Afterwards, Pittsburgh's defense held Cincinnati to no scoring. Led by James Harrison, who finished the game with 3 sacks, they held Cincinnati to only 232 net yards.
Question: How many points did Pittsburgh lead by at halftime?
Answer: 21