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

Q: vJtmxQmHEq, yobgAtmxQmMeoLz

A: tmxQm
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Q: KfjqnJLciTXqkJK, yqfRcfqnJLcisSB

A: qnJLci
****
Q: CeBsPJvc, rlzBsPJtIWA

A:
BsPJ
****