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

[Q]: CUxfOt, dyxfNp
[A]: xf


[Q]: AkYuNemHGBEDF, uluNemHGAycbWX
[A]: uNemHG


[Q]: TGEFFJvZCFpM, tNMpEFFJvZCFKtvANTk
[A]:
EFFJvZCF