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

Q: gHFwDorPbNPORVgdLW, AfqDQvCGFwDorPbNPVPVmbQ

A: FwDorPbNP
****
Q: dsngGP, KvnglB

A: ng
****
Q: XDrDDmkqZhQ, tjDmkqBJ

A:
Dmkq
****