instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
LiiFMMLGfNHVnnga, beXMMLGfNHVsjdfdN
answer:
MMLGfNHV


question:
QKlzsmHyBcC, snPtzsmHdMIv
answer:
zsmH


question:
PAJwhpzXajwvhGGyqJKq, kiCxbjrJwhpzXajwxpomUot
answer:

JwhpzXajw