Find the Integer with Odd Occurrence

You are given a list of integers. In this list, exactly one integer appears an odd number of times, while all the other integers appear an even number of times.

Your task is to identify and output the integer that occurs an odd number of times. It is guaranteed that such an integer always exists.

inputFormat

The input is provided via standard input (stdin) and consists of two lines. The first line contains a single integer n, the number of elements in the list. The second line contains n space-separated integers.

outputFormat

Print to standard output (stdout) a single integer — the one that appears an odd number of times.## sample

7
1 2 3 2 3 1 3

3