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

[Q]: YRLHFm, odLHCI
[A]: LH


[Q]: zfUPUDeKbCMQa, BkAJFJUDeKbCMZmkFu
[A]: UDeKbCM


[Q]: AtKqeSXKjFR, aqjgMKqeSXKjQAFH
[A]:
KqeSXKj