instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
sdGIVJPsWWszKPCGk, ghRJPsWWszKcJUg
answer:
JPsWWszK


question:
hUpEbyvEcQ, dHpEbyvEvwsXcN
answer:
pEbyvE


question:
aYBjDIolycgCCkQqwSyMrFR, QleSgDolycgCCkQrSaO
answer:

olycgCCkQ