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

Q: wLLwjL, arLwXm

A: Lw
****
Q: FCKbAgSVgj, wAEAWbAgSVSVwD

A: bAgSV
****
Q: uLAvxCqWK, qtAvxCXsOk

A:
AvxC
****