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

[EX Q]: sdGIVJPsWWszKPCGk, ghRJPsWWszKcJUg
[EX A]: JPsWWszK

[EX Q]: YcgVJVACcQE, JsJVACcSz
[EX A]: JVACc

[EX Q]: JybSPjsipfyxBSxxtfI, KooQhESPjsipfyvkyxQEv
[EX A]:
SPjsipfy