instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
pySBCdpe, AEBCdOR
answer:
BCd


question:
HiEuutntEBpU, fdkqEuutntEBABdGZRND
answer:
EuutntEB


question:
IONGwibfQZZjinVuGqUU, RHLFSdXIeNGwibfQZZXrjmFcc
answer:

NGwibfQZZ