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

Example Input: EOacPYivmmUlYenynBqAwx, MoZWMOeXmUlYenynBEendWg
Example Output: mUlYenynB

Example Input: bOvlVNWf, iivlVzWt
Example Output: vlV

Example Input: LNHaYCoTgboZ, mqspaYCoTgbDwV
Example Output:
aYCoTgb