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

[EX Q]: jinzsW, SMnzaW
[EX A]: nz

[EX Q]: uGDJixAmSiVaFRmfKRM, NsTGxsJixAmSiVageSw
[EX A]: JixAmSiVa

[EX Q]: qxHuVLUExW, rYSGuVLUCeH
[EX A]:
uVLU