CF23A.You're Given a String...

You're given a string of lower-case Latin letters. Your task is to find the length of its longest substring that can be met in the string at least twice. These occurrences can overlap (see sample test 2).

给你一个由小写拉丁字母组成的字符串。你的任务是找出该字符串中最长的子串的长度，该子串在字符串中至少出现两次。这两次出现可以重叠（参见样例测试 2）。

The first input line contains the string. It's guaranteed, that the string is non-empty, consists of lower-case Latin letters, and its length doesn't exceed 100.

第一行输入包含一个字符串。保证该字符串非空，仅由小写拉丁字母组成，且长度不超过 100。

Output one number — length of the longest substring that can be met in the string at least twice.

输出一个数字——字符串中至少出现两次的最长子串的长度。