instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
gfXPLNzsyfEotmHL, oJeXPLNzsyJuXP
answer:
XPLNzsy


question:
hVQJkZyKfPoOQEukfAbXDpB, qpojyxWkZyKfPoOQEZkUI
answer:
kZyKfPoOQE


question:
mADHZXpqI, jdDHZXueUP
answer:

DHZX