First Non-Repeating Character

You are given a string s and your task is to find the first non-repeating character in it. A non-repeating character is defined as a character that appears exactly once in the string. If there is no such character, your program should output an underscore (_).

The input is read from standard input (stdin) and the result must be written to standard output (stdout).

Note: When counting characters, consider the string in the order provided. Once a character is found that occurs exactly once, it should be immediately output. If no unique character exists, output _.

inputFormat

The input consists of a single line string s.

Example:

aabbccdde

outputFormat

Output a single character which is the first non-repeating character in the string. If there is no such character, output _.

Example:

e

## sample

aabbccdde

e

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