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: OezHeoe, ouUzHemU

A: zHe
****
Q: kdJKDIRFSponLB, EcrWvoJKDIRFYRUGiK

A:
JKDIRF
****