Task: Question Answering
Input (English): Passage: Hoping to add to a seven-game winning streak, the Broncos traveled to the O.co Coliseum for an AFC West rematch with the Oakland Raiders. The Broncos jumped out to a 13-0 lead, with quarterback Peyton Manning throwing a 6-yard touchdown pass to tight end Joel Dreessen, followed by field goals of 43 and 34 from placekicker Matt Prater, with the latter field goal occurring early in the second quarter. The Raiders got on the scoreboard late in the first half, with quarterback Carson Palmer throwing a 6-yard touchdown pass to running back Darren McFadden. The Broncos added to their lead in the third quarter, with a 20-yard field goal by Prater, a 1-yard touchdown run by running back Knowshon Moreno and a 33-yard field goal by Prater. A 56-yard touchdown pass from Palmer to wide receiver Darrius Heyward-Bey (with a failed two-point conversion attempt) was the only scoring play of the fourth quarter, and the Broncos ran out the final 5:36 of the game. With the win, the Broncos earned their first season sweep of the Raiders since 2006, and also swept their division rivals on the road for the third time in four seasons. 
Question: How many yards was Carson Palmer's longest touchdown pass? 
Answer type: Number 
Output (English): 56.