instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
uGDJixAmSiVaFRmfKRM, NsTGxsJixAmSiVageSw
answer:
JixAmSiVa


question:
apGMPThLTCw, LvMPThYW
answer:
MPTh


question:
TnbLNKnNSs, NhDLNKnNRd
answer:

LNKnN