Longest Unique Substring

Given a string S, your task is to find the length of the longest contiguous substring in which every character is unique. In other words, you need to determine the maximum integer L such that there exists a substring S[i...j] with all distinct characters, where

$$L = \max\{j - i + 1 \; : \; S[i...j] \text{ has all unique characters}\}$$

For example, if S = "abcabcbb", one of the longest substrings with unique characters is "abc", so the answer is 3.

inputFormat

The input consists of a single line containing the string S. Note that S may include spaces and other printable ASCII characters.

outputFormat

Print a single integer representing the length of the longest substring of S that contains only unique characters.

abcabcbb

3