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

[EX Q]: XSnVeAjWLFWTgwmf, WsByLAjWLFWnQfl
[EX A]: AjWLFW

[EX Q]: DGvUCrUVlUnQBShkWnfnceGasvI, NfzGUnQBShkWnpLMnY
[EX A]: UnQBShkWn

[EX Q]: fVqIDnslhbUXs, hZADnslhpsb
[EX A]:
Dnslh