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

[EX Q]: DQBpdnwVDcnCDEWpD, gAtCdnwVDcnCYv
[EX A]: dnwVDcnC

[EX Q]: oUEcuLINTDdvdOne, thzWccuLINTDQfNZwH
[EX A]: cuLINTD

[EX Q]: ITdzMrgZnffqW, oRQMrgZnfhh
[EX A]:
MrgZnf