This question writer had a roommate during his freshman year was a quirky business major. When we first met, we got along well and realized it was going to be a great $1$st semester. We decided to get dinner together, and on the way out, he locked and unlocked our door six times, opening the door each time in between, then closing the door tightly, and locking it before unlocking it again in the same manner. By the $3$rd time, this question writer decided to wait by the elevator and ponder his life choices. This act of locking and unlocking the door is considered a$($n$)$: