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

[EX Q]: RwduMBkDazrwZP, UPzcwtWMBkDazrAw
[EX A]: MBkDazr

[EX Q]: uHGHiARtdJbuG, OdZmiARtdrhC
[EX A]: iARtd

[EX Q]: ZLBaqhWvDO, aHqhWvAJt
[EX A]:
qhWv