Cheating on Queue

Chef went to the store and saw a long queue. There are $N$ people in the queue (numbered $1$ through $N$ from the front of the queue to the back); as it usually happens in such a situation, each person has a certain anger level. Let's denote the anger level of the $i$-th person by $a_i$. Chef wants to finish shopping as fast as possible, so he decided to try jumping the queue instead of just st