instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
kyADtWLlnmYv, tcaKvDtWLlnvBq
answer:
DtWLln


question:
ZKMRTxCxbsbX, iovHrMRTxCxbsjv
answer:
MRTxCxbs


question:
oTERHM, uQERnT
answer:

ER