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

kUoqCMPFTqGE, guoqCMPkwJs
oqCMP

yJRITYgVTSNsPjG, NSIdKYgVTSNmj
YgVTSN

LqhfYoCjezqXKS, OmjTnkYoCjezqXAGRH

YoCjezqX