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

Q: zbSNNVc, agSNNtOQ

A: SNN
****
Q: lOedgdw, aoedgpn

A: edg
****
Q: mCpKQPUZoL, qvWpKQPwA

A:
pKQP
****