Permutation#354
A sequence of positive integers is given. Determine whether it is a permutation of the first positive integers.
The first line contains the integer (n \leq 10000), followed by a sequence of positive integers. Each number does not exceed 2 \cdot 10^6.
Print if the sequence is a permutation. Otherwise, print the smallest number that is missing from the sequence.
Example 1
Example 2