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

Example Input: JKZiYILNeNQbJyznES, PHKILNeNQbJylltYH
Example Output: ILNeNQbJy

Example Input: YHLJZrFQ, aSLJZQuo
Example Output: LJZ

Example Input: fhTDav, hFTDSy
Example Output:
TD