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

yKtQOhYvrJVH, HQsTQOhYvPP
QOhYv

DQVkAbWTTPhoBx, TeWTTPhonxcIKL
WTTPho

afpFxZWxxvcIEP, BhpFxZWxxojSfbO

pFxZWxx