instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
jJjsASFfCqVV, AkjsASFfBFwPy
answer:
jsASFf


question:
fBpRXPkikQokGVeS, FwUbKXkikQokGos
answer:
kikQokG


question:
smRmCAmfpOOWPAglFj, LnCAmfpOOkYqyIbt
answer:

CAmfpOO