Due to the Steelers' loss to the Ravens the previous day, the Bengals entered the game as the AFC North champions. The Bengals rushed out to a 14-0 lead in the first half on a McCarron touchdown pass and a Mohamed Sanu rush, but Denver cut the deficit to 11 points as Brandon McManus nailed a short 23-yard field goal with just 18 seconds remaining before halftime. In the second half, momentum shifted mightily after a missed field goal by Mike Nugent in the third. Emmanuel Sanders hauled in an 8-yard pass from Brock Osweiler to cut the deficit to 14-10, and Denver claimed the lead for the first time in the game on a 39-yard touchdown run by C.J. Anderson with 11:17 remaining in the 4th Quarter. The Bengals marched down the field to tie the game on Mike Nugent's season-long 52-yard field goal, making the score 17-17 at the end of regulation. The tired Bengals failed to put any  points on the board in the extra period, allowing a 37-yard McManus field goal to make the score 20-17 Denver. A botched snap on the ensuing Bengals drive was recovered by the Broncos, ending the game and Cincinnati's hopes for a first-round bye in the playoffs. With the loss, the Bengals fell to 11-4 on the season. The loss was also the 10th straight in Denver for the Bengals, dating back to 1975.
Question: How many touchdowns did the Bengals lead by in the first half?
Answer: 2