instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
WTnsmP, INnsIM
answer:
ns


question:
ugDpSMRvHM, DDwSMRvxw
answer:
SMRv


question:
FinpJsoqYAFkRVacMn, IerhabeopJsoqYAFkRlzse
answer:

pJsoqYAFkR