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

[Q]: AuSFmN, crSFXM
[A]: SF


[Q]: sRTQgRgRUjEooapKdR, vzsBgRUjEooLBkYeH
[A]: gRUjEoo


[Q]: nORLkc, wLRLNx
[A]:
RL