Longest Substring Without Repeating Characters

You are given a string S. Your task is to compute the length of the longest substring of S that contains no repeated characters.

Consider a substring as a contiguous sequence of characters within the string. For example, if S = "abcabcbb", then the answer is 3 because the longest substring without repeating characters is "abc".

The solution should be efficient enough to handle large strings.

Note: The input will be provided as standard input (stdin) and the output should be printed to standard output (stdout).

inputFormat

A single line containing the string S.

outputFormat

An integer representing the length of the longest substring of S in which all characters are unique.## sample

abcabcbb

3