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: BfCCzPNLBbwCoxMVAG, vhwNLBbwCbH

A: NLBbwC
****
Q: LbOJEoqjQtI, VeAfJEoqjBBTD

A:
JEoqj
****