Do you know how hard it is to pull the trigger?
The famous dictator Lee Xi Seung has an army of 105 at his disposal. He numbered them from 0 to 105−1. The lower the number a person has, the higher his commanding abilities. Then he repressed n of them. Now the dictator is going to conduct a small victorious war with a neighboring state. Therefore, he urgently needs to choose the most talented military who is alive.
The first line contains the number of repressed n(1≤n<105). The second line contains their numbers in Lee Xi Seung's list — all numbers less than 105.
Print one number — the number of the most talented alive military.