First Unique Element

You are given a list of numbers. Your task is to find and output the first unique (non-repeating) element from this list. A unique element is one that appears exactly once in the list. If no unique element is found, print None.

The numbers in the list can be integers, floating-point numbers, or negative numbers. The input is provided via standard input and the output should be printed to standard output.

inputFormat

The input is given on a single line through standard input. The first number is an integer n representing the number of elements in the list. It is followed by n space-separated numbers.

outputFormat

Output the first unique number from the list. If no unique number exists, output None.

5 1 2 2 1 3

3