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

[Q]: YWNPkA, LuNPnN
[A]: NP


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


[Q]: HIAkieQJcoE, yYXoxakieQJcDh
[A]:
kieQJc