First Non-Repeating Character

You are given a string s. Your task is to find the first character in the string that does not repeat. If every character in the string appears more than once, output No unique characters found.

For example, given the string abcdef, the answer is a because it is the first character that uniqueness is maintained. Similarly, given aabbccdde, the answer is e since e is the first non-repeating character. If no such character exists, you should print No unique characters found.

The solution should read input from standard input (stdin) and output the result to standard output (stdout).

inputFormat

The input consists of a single line containing the string s. The string may include letters (both uppercase and lowercase), digits, and special characters. The length of s is between 0 and 10,000.

outputFormat

Output a single line: the first non-repeating character in the input string s, or the message No unique characters found if every character repeats.

abcdef

a