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

QEEVsnbQIgrxaZmflaZ, dPSbljkdQIgrxaZmgVzMT
QIgrxaZm

wlFcxOHoXC, IWFcxOIWTk
FcxO

RkPVoIGqmKlBGHcS, oWjxQGqmKlBGikxV

GqmKlBG