Hoping to rebound from their loss to the Rams, the Broncos returned home for an AFC duel against the Miami Dolphins &#8212; the Broncos' first home game in exactly one month. The Dolphins grabbed the early lead, with running back Daniel Thomas rushing for a 3-yard touchdown. The Broncos subsequently got on the scoreboard, with a 38-yard field goal by placekicker Brandon McManus. The Dolphins added to their lead early in the second quarter, with quarterback Ryan Tannehill rushing for a 1-yard touchdown. The Broncos cut into the Dolphins' lead, with quarterback Peyton Manning connecting on a 5-yard touchdown pass to wide receiver Demaryius Thomas, however, the Dolphins responded, with Tannehill throwing a 10-yard touchdown pass to wide receiver Mike Wallace. Another touchdown pass from Manning to Demaryius Thomas &#8212; from 14 yards out &#8212; narrowed the Dolphins' lead to 21-17 just before halftime. The Broncos drove to as far as the Dolphins' 7-yard line on the initial possession of the second half, but after Manning was sacked by Dolphins' linebacker Jelani Jenkins for an 8-yard loss, McManus missed on a 33-yard field goal attempt. After the Broncos' defense forced a Dolphins' punt, return specialist Isaiah Burse fumbled deep in Broncos' territory, giving the football back to the Dolphins. Four plays later, Tannehill connected with wide receiver Jarvis Landry on a 5-yard touchdown pass to give the Dolphins a 28-17 lead at the 2:15 mark of the third quarter. The Broncos then reeled off 22 unanswered points. Early in the fourth quarter, Manning threw his third touchdown pass of the game to Demaryius Thomas &#8212; from 5 yards out &#8212; coupled with a two-point conversion pass to wide receiver Emmanuel Sanders. After forcing a Dolphins' punt, the Broncos grabbed their first lead of the game at the 5:05 mark of the fourth quarter, with running back C. J. Anderson rushing for a 10-yard touchdown. On the third play of the Dolphins' next possession, Tannehill was intercepted by Broncos' safety T. J. Ward, who advanced the football all the way to the Dolphins' 8-yard line. Two plays later, Manning threw a 2-yard touchdown pass to wide receiver Wes Welker to increase the Broncos' lead to 39-28 with 3:17 remaining in the fourth quarter. The Dolphins attempted a rally, with Tannehill connecting on a 1-yard touchdown pass to Landry, coupled with running back Lamar Miller rushing for a two-point conversion, with 1:37 remaining in the game. However, the Dolphins' onside kick attempt was unsuccessful, and the Broncos subsequently ran out the clock. Demaryius Thomas' streak of 100-yard receiving games ended at seven games, one shy of the NFL record that was set by Detroit Lions' wide receiver Calvin Johnson in 2012.
Question: How many points were the Dolphins leading by at the end of the first half?
Answer: 4