First Non-Repeating Character

Given a string, your task is to find and output the first character that does not repeat in the string.

You should iterate over the characters of the string from left to right, count the frequency of each character, and then identify the first character with a frequency of one. If there is no such character, output an empty string.

The solution should handle edge cases such as an empty string.

In mathematical terms, if we let \( f(c) \) denote the frequency of the character \( c \) in the string \( s \), then find the smallest index \( i \) such that \( f(s_i)=1 \). If no such index exists, return an empty string.

inputFormat

The input consists of a single line containing the string \( s \). The string can contain any printable characters.

outputFormat

Output the first non-repeating character of the provided string. If there is no such character, output an empty line.

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