Palindrome Search

A palindrome is a string that reads the same forwards and backwards.

Your task is to find a substring within the given string that is a palindrome and has a length greater than one.

Input

You will be provided with a single string composed of lowercase Latin letters.

Output

Output a substring from the given string that is a palindrome with a length greater than one. If no such substring exists, output 0. If there are multiple valid substrings, you may output any one of them.

Examples