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

Q: RtAchtNymcswVk, FWRuRchtNymcswUkoERHyML

A: chtNymcsw
****
Q: DhhYhrqVMXSoyvXQwqPKzWARAP, CaMXSoyvXQwqcDDtMsVqD

A: MXSoyvXQwq
****
Q: yhQkcarpmSm, lgVzkcarpmtg

A:
kcarpm
****