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

[EX Q]: OUNqomxFcLXhWdfB, gdqomxFcLHQPCu
[EX A]: qomxFcL

[EX Q]: yjoJzBGdwfOhsceoOpoap, uSLMdBGdwfOhsIQHBijd
[EX A]: BGdwfOhs

[EX Q]: xBhvuAyOx, nWvuAOO
[EX A]:
vuA