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

[Q]: OyXwTWbLByC, yODnTWbLWYzc
[A]: TWbL


[Q]: kyADtWLlnmYv, tcaKvDtWLlnvBq
[A]: DtWLln


[Q]: kdmfzZ, XNmfEJ
[A]:
mf