instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
gTjTwC, OUjTgM
answer:
jT


question:
CiTNsbepy, DFNsbeZl
answer:
Nsbe


question:
YWLOXyZZeiuXgDM, nwOXyZZekRRv
answer:

OXyZZe