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

QECPAHsg, bUfPAHOWb
PAH

DQBpdnwVDcnCDEWpD, gAtCdnwVDcnCYv
dnwVDcnC

DCAiGzAXPNtILUXWRRtgpW, odHVLPNtILUXWRRzBPnrvr

PNtILUXWRR