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

AuSFmN, crSFXM
SF

hVQJkZyKfPoOQEukfAbXDpB, qpojyxWkZyKfPoOQEZkUI
kZyKfPoOQE

rXasPyjoieUNpSXsIK, MjtKmvfoieUNpSXdEs

oieUNpSX