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

Q: QeNePjbLBKbDOuAVTJtXL, xjPVOyPbLBKbDOuDsMSEF

A: bLBKbDOu
****
Q: XjYkMfARxWBSBjuXyDrFt, EtUxIfiHkMfARxWBSckTLTTnR

A: kMfARxWBS
****
Q: MeUjOc, LjUjqj

A:
Uj
****