Smallest Missing Positive Integer

Given an array of integers, your task is to find the smallest positive integer that is missing from the array. The input begins with an integer n which represents the number of elements in the array, followed by n space-separated integers. The answer is the smallest natural number (i.e. a number greater than 0) that does not appear in the array.

Example:

Input:
6
1 3 6 4 1 2
Output:
5

</p>

The problem can be formalized as: Find the smallest positive integer m such that m \notin A, where A is the set of positive integers present in the array.

inputFormat

The input is given from stdin and has the following format:

• The first line contains an integer n (0 ≤ n ≤ 10⁵), the number of elements in the array.
• If n > 0, the second line contains n space-separated integers.

If n is 0, then the array is empty.

outputFormat

Output a single integer to stdout representing the smallest missing positive integer.

## sample

6
1 3 6 4 1 2

5