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

rEHxRBOktYreNkK, NCOktYreFFCFwi
OktYre

BrDGrTD, PBHDGrDw
DGr

mIxInpzgVrzcScsSeo, KSQfEDHMnRzgVrzcScsSdBPyNkzV

zgVrzcScsS