instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
UZbmGVDzIaf, qfHwqGVDzIsd
answer:
GVDzI


question:
ksRxEVrz, cOMRxEViwF
answer:
RxEV


question:
ulSEgvuohHvJwwenOCEVIsVMPV, FlhHvJwwenOAAHz
answer:

hHvJwwenO