SP1811 LCS - Longest Common Substring

A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occurrences at least once in a string. Now your task is simple, for two given strings, find the length of the longest common substring of them. Here common substring means a substring of two or more strings.

The input contains exactly two lines, each line consists of no more than 250000 lowercase letters, representing a string.

The length of the longest common substring. If such string doesn't exist, print "0" instead.