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

[Q]: BeEgLISxThm, UGLISxEtP
[A]: LISx

[Q]: UiaECWZf, gRyaECWLGRl
[A]: aECW

[Q]: DPdLWr, WJdLTH
[A]:
dL