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

[Q]: BUvWkxrAvDQG, rHrkxrAkCE
[A]: kxrA


[Q]: NUuLSmDjCKcJPc, lGGSLIDjCKcJBo
[A]: DjCKcJ


[Q]: vSyQTCtksHfVEpGIhvIdWD, UdPunzCtksHfVEpzFXVU
[A]:
CtksHfVEp