instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
aIZIsqL, wxSZIsEnO
answer:
ZIs


question:
yjoJzBGdwfOhsceoOpoap, uSLMdBGdwfOhsIQHBijd
answer:
BGdwfOhs


question:
bUHPpvVtFQNSpUdg, zggEFoKBHPpvVtFQNHXsc
answer:

HPpvVtFQN