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

[EX Q]: KvPFobZEGs, eKFobZEtnm
[EX A]: FobZE

[EX Q]: DhhYhrqVMXSoyvXQwqPKzWARAP, CaMXSoyvXQwqcDDtMsVqD
[EX A]: MXSoyvXQwq

[EX Q]: jmYyvDyuLGDtUxp, SDRtDyuLGEP
[EX A]:
DyuLG