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

DQVkAbWTTPhoBx, TeWTTPhonxcIKL
WTTPho

aIZIsqL, wxSZIsEnO
ZIs

qcjKgzUffbxyzYWijXlw, fKJzQZVjKgzUffbxyvj

jKgzUffbxy