instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
lMRuEThD, wqQRuEKp
answer:
RuE


question:
pBDnbfrAxJfVhPBxheXZGp, LMtorAxJfVhPnnaed
answer:
rAxJfVhP


question:
BeEgLISxThm, UGLISxEtP
answer:

LISx