Find the Unique Element (Appears Once)

You are given a list of integers where every integer appears exactly three times except for one integer which appears exactly once. Your task is to find and output this unique integer.

Hint: Use bitwise operators to achieve a solution with optimal time and space complexity.

The solution must read the input from stdin and write the result to stdout. The input format is described below.

inputFormat

The first line of input contains an integer n representing the number of elements in the list. The second line contains n space-separated integers.

Example:

4
2 2 3 2

outputFormat

Output the unique integer that appears exactly once.

Example:

3

## sample

4
2 2 3 2

3