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: yxJxNRLEnKGHziJtfb, KfReWhEnKGHzitzfPWzK
Example Output: EnKGHzi

Example Input: YRZKpGz, PXDZKpne
Example Output:
ZKp