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

OFbCjZDoRRlLsMU, DcCjZDoRRtld
CjZDoRR

cUCQXEFSgRZjK, RYdvUQXEFSgRZVlwx
QXEFSgRZ

ovKVMG, BuKVQL

KV