Longest Unique Substring

Given a string s, your task is to find the longest substring of s that contains no repeating characters. If there are multiple substrings with the maximum length, return the one that appears first in s.

You need to output two items: the length of this substring and the substring itself. If the input string is empty, output 0.

Note: For any formulas used, please use the LaTeX format. In this problem, you may use the two-pointer (sliding window) technique.

inputFormat

The input is given from stdin and consists of a single line containing the string s.

Example:

abcabcbb

outputFormat

Output the length of the longest substring with all unique characters, followed by a space, then the substring itself. If the string is empty, simply output 0.

Example:

3 abc

## sample

0