Longest Substring Without Repeating Characters

You are given a string s. Your task is to find the length of the longest substring that does not contain any repeating characters.

For example, given the string abcabcbb, the answer is 3 because the longest substring without repeating characters is abc.

The problem can be formulated as follows:

Find \( L \), where \[ L = \max_{0 \leq i \leq j < n} \{ j-i+1 \mid s[i\ldots j] \text{ has all unique characters} \}\]

Read the input from standard input and write the result to standard output.

inputFormat

The input consists of a single line containing the string s. The string may contain spaces and special characters.

You should read the input from stdin.

outputFormat

Output a single integer which is the length of the longest substring of s that does not contain repeating characters.

The output should be written to stdout.

## sample

abcabcbb

3