Based on the given tweet, determine the level of anger the author is experiencing. Choose from the following options: 0: no anger can be inferred, 1: low amount of anger can be inferred, 2: moderate amount of anger can be inferred, 3: high amount of anger can be inferred.
Tweet: @AmericanAir I am irate at you check-in system. I have tried to checkin all day and it wouldn't let me do it because I had no seat assigned
3: high amount of anger can be inferred