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

Q: xfZYYDKEqoRRu, ztCeYYDKEqoPG

A: YYDKEqo
****
Q: mmDhYqPJC, qThYqxW

A: hYq
****
Q: qtcVthKWREDQbFvNFd, TELeKWREDQbFvGUCfjb

A:
KWREDQbFv
****