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

Q: oiNEYHxbvAb, bcDDdEYHxbCREd

A: EYHxb
****
Q: iMwanJBuMdiZDL, kIafHeBuMdiZmKNA

A: BuMdiZ
****
Q: xOqLaj, QxqLQe

A:
qL
****