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

hVQJkZyKfPoOQEukfAbXDpB, qpojyxWkZyKfPoOQEZkUI
kZyKfPoOQE

qczzCr, zDzzUI
zz

VijYfXjiMum, iKCYfXjyoGF

YfXj