instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
OhMVLbQhBxEaOZY, iDVLbQhBxBiiD
answer:
VLbQhBx


question:
rvLoiycpZw, idcvoiycpcLyD
answer:
oiycp


question:
kfNmzLtn, igmzLJzI
answer:

mzL