instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
KKebLWQCQzVIojj, nxQCQzVIopD
answer:
QCQzVIo


question:
kyADtWLlnmYv, tcaKvDtWLlnvBq
answer:
DtWLln


question:
HlmpKGhYfVRCVSzBsMu, hiFOmpKGhYfVRCbSHWZU
answer:

mpKGhYfVRC