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

Q: dxqZUOvRprXyFfjQfTWBhR, biSVjOvRprXyFfDtuFWQ

A: OvRprXyFf
****
Q: eNuawupVqQ, RIawuplUIf

A: awup
****
Q: jkGcUm, dxGcSI

A:
Gc
****