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

[EX Q]: fAsWQxuyBevvLogrSrgg, tmdBEUxuyBevvLogXjiMCbh
[EX A]: xuyBevvLog

[EX Q]: JAfPtjqqUYMD, cpXItjqqFN
[EX A]: tjqq

[EX Q]: LwqCKwDzL, gJqCKwHISe
[EX A]:
qCKw