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

OrcQOvMBhmwP, mnWrzcQOvMBnLwI
cQOvMB

XqyPjqNZDEK, EfwPjqNgjIP
PjqN

SrSXzgHLYxaypeBmqq, RDMgHLYxayCldZS

gHLYxay