First Non-Repeating Character

You are given a string s. Your task is to find the index of the first non-repeating character in s. If every character appears at least twice, output -1.

For example, if the input string is leetcode, the first non-repeating character is 'l' at index 0. If the input is loveleetcode, the answer is 2. In the case of aabbcc, no such character exists so the output is -1.

Note: The string contains only ASCII characters.

inputFormat

The input consists of a single line containing the string s.

Input Format:

s

outputFormat

Output a single integer, which is the index of the first non-repeating character in the string. If no such character exists, output -1.

Output Format:

result

## sample

leetcode

0