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

[EX Q]: yxJxNRLEnKGHziJtfb, KfReWhEnKGHzitzfPWzK
[EX A]: EnKGHzi

[EX Q]: ugDpSMRvHM, DDwSMRvxw
[EX A]: SMRv

[EX Q]: ediBKNZHKB, EVXaJwiBKNZHgOEHF
[EX A]:
iBKNZH