Str with Longest Len

Find the length of the longest string that is both a proper prefix and a proper suffix of the given string. It must be shorter than the whole string, the prefix and suffix may overlap, and the empty string of length 0 is valid.

This site uses a standard input/output protocol.

输入格式

One line containing a lowercase string S of length 1..1000000.

输出格式

Output a single integer, the answer.

样例 1

输入：

abbabba

输出：

4

样例 2

输入：

codility

输出：

0

样例 3

输入：

aaaa

输出：

3

样例说明

Example 1: abba appears at both the start and the end, so the length is 4. Example 2: there is no non-empty common proper prefix and suffix, so 0. Example 3: aaa is allowed to overlap, so the length is 3.