Answer: No I'm not but their success is insane and it's amazing what they've been able to do these past couple years.
Explanation: Fan of a few of their songs though! Just not really a part of any fandom really.
I would say the answer is Bb!
G G A A B(flat) F D D C C B(flat) F F B(flat) F B(flat) F F F F F B(flat)
D .complicated hope this helped