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

Example Input: YKpdeJQhzyYiPoODACUu, mjmnIlCehzyYiPoOzZ
Example Output: hzyYiPoO

Example Input: QaxEaxdouNyyvNAn, wRjWSaxdouNyyrriQiG
Example Output: axdouNyy

Example Input: QaQezhcxRwglegoQaycS, ANlTTxRwglegozEbN
Example Output:
xRwglego