longlong
Source: hackerearth
Difficulty: MEDIUM

You are given a string S. Find the length of its the longest substring which occurs at least two times. Occurences can intersect.

Input
One line containing a string S consisting of lowercase Latin letters.

Output
Output one integer - answer to the question.

Constraints
1 ≤ length of S ≤ 1000000

SAMPLE INPUT
abacaba

SAMPLE OUTPUT
3