CrossFit Open 13.5 Workout

AMRAP in 4 Minutes:
15 Thrusters (#100/65)
15 Chest to Bar Pull-ups
*There is a 4 minute bonus for every 90 reps (3 rounds) completed. If an athlete makes 90 reps in the first 4 minutes, their workout is then 8 minutes in length. Same for the next 90 reps per 4 minutes, and upward.