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

[EX Q]: slTUxy, oqTUYa
[EX A]: TU

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

[EX Q]: KfVRsxkuiNozvZjeo, UvVyguiNozvZIu
[EX A]:
uiNozvZ