Search for a line

In a sequence of lowercase Latin alphabet characters, your task is to identify the longest subsequence where all characters are distinct and appear consecutively.

Develop a program named SUBSTR that, given such a sequence, determines the first subsequence composed entirely of unique characters.

Input

The input consists of a sequence distributed across multiple lines for convenience. Each line contains up to 100 characters, and the entire sequence does not exceed 10,000,000 characters in length.

Output

The output should be a single line containing the first longest subsequence of consecutive characters without any duplicates.

Examples