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

lypuwWy, jRpuwcE
puw

krnkpodgfpCKtfCqyzUbymWbxi, DydgSWpCKtfCqyzDaMsjqc
pCKtfCqyz

iZARjpoHdZMpvW, NMtJsOdARjpoHdZDgwhxA

ARjpoHdZ