Longest Unique Substring

Given a string s, find the length of the longest substring without repeating characters. A substring is a contiguous sequence of characters within the string. For example, for the input "abcabcbb", the longest substring without repeating characters is "abc", which has a length of 3.

In mathematical terms, if the substring spans from index i to j, then its length is given by \( j-i+1 \). Your task is to implement an efficient solution to compute this value.

inputFormat

The input consists of a single line which contains the string s. The string may include any printable characters and its length can be zero.

outputFormat

Output a single integer: the length of the longest substring of s that contains no repeating characters. The result should be printed to stdout.

abcabcbb

3