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

[Q]: yQCDWefwvrPP, RwoMDWefwhSxTR
[A]: DWefw


[Q]: TdvkBvVyJcSdYGGPfnyml, rIvIvVyJcSdYhtxG
[A]: vVyJcSdY


[Q]: cYqKeoBKnYttVGnr, OyrZyVqBKnYttVGZxjZqrT
[A]:
BKnYttVG