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

Q: jXbgnl, lUbglP

A: bg
****
Q: cvZfWOwa, xOfWOhZs

A: fWO
****
Q: DcpTtduxxWfVs, VbUmqduxxWWsHK

A:
duxxW
****
