Context: The Steelers traveled to Miami to take on the Dolphins. In the first quarter, the Dolphins struck first when Andrew Franks kicked a 30-yard field goal for a 3-0 lead. The Steelers got on the board later on in the quarter taking the lead when Darrius Heyward-Bey ran for a 60-yard touchdown (with a successful 2-point conversion) for an 8-3 game. In the second quarter, it was all Dolphins as they closed out the half by first coming within 2 when Franks kicked a 23-yard field goal to make the score 8-6. The Dolphins eventually took the lead back when Franks kicked another 30-yard field goal for a 9-8 game. They would move ahead by a touchdown when Damien Williams ran for one from a yard out to take a 16-8 lead at halftime. In the third quarter, the Dolphins got back to work when Jay Ajayi ran for a 1-yard touchdown to make the score 23-8 for the only score of the period. The Steelers tried to rally when Ben Roethlisberger found Cobi Hamilton on a 23-yard touchdown pass shortening their deficit to 8, 23-15. Though the Steelers' rush defense stalled with less than a minute left in the game and Ajayi ran for a 62-yard touchdown to seal the game with the final score 30-15. With the loss, the Steelers fell to 4-2. Ben Roethlisberger would be knocked out of the game due to injury in the second quarter. Though he played in the second half. The Steelers still remained in first place with the Ravens' loss to the Giants.

Question: How many points did the Dolphins win by?

Answer:
15