In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

Example Input: txJhzNeBj, qLJhzNesV
Example Output: JhzNe

Example Input: osmJJcZlDAXBgJFsJKa, rzPNlDAXBgJYrgXlH
Example Output: lDAXBgJ

Example Input: xYLZxjqzOCqErhuhnwHOlGmuUO, NIKfbzLWqzOCqErhuhkaYoqygD
Example Output:
qzOCqErhuh

