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

[Q]: hVQJkZyKfPoOQEukfAbXDpB, qpojyxWkZyKfPoOQEZkUI
[A]: kZyKfPoOQE


[Q]: ARGchkRez, kUwchkZPE
[A]: chk


[Q]: ozSDFt, JxSDPs
[A]:
SD