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

mCxQTIaXN, mWQTIaxzPT
QTIa

JjEQVKijeyEQ, dwSVKijeywCTvb
VKijey

BDtpHTBGOOCs, pxtZQpHTBGCm

pHTBG