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

rszjOPpbXm, pnBujOPpWHz
jOPp

kIBDjQLEZepVNHqnKqhine, hTZepVNHqnYTajyzv
ZepVNHqn

ETkzukKoCvPPIykDZAZVT, rqutBEKoCvPPIykDiKESR

KoCvPPIykD