CrossFit Open 12.5 Workout

7 min AMRAP:

3 Thrusters
3 Chest-to-bar Pull-ups
6 Thrusters
6 Chest-to-bar Pull-ups
9 Thrusters
9 Chest-to-bar Pull-ups
12 Thrusters
12 Chest-to-bar Pull-ups
....etc.