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

[Q]: CiTNsbepy, DFNsbeZl
[A]: Nsbe


[Q]: vSFxjd, AHFxpi
[A]: Fx


[Q]: xVgpfQzgj, ktJCgpfQSX
[A]:
gpfQ