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

Q: GrvtMjEvRlmN, ifGOWMjEvRPSOZK

A: MjEvR
****
Q: OyrqfQQnzOFUzrkDM, iBkQQnzOFewhjvO

A: QQnzOF
****
Q: hUaERE, nZaElK

A:
aE
****