instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
pIkAtJHVcvzzZVz, btWerNSHVcvzzZTz
answer:
HVcvzzZ


question:
sGrHRmELarByxp, cDCUnmELarBXbEfM
answer:
mELarB


question:
erDviqU, iuDviHzH
answer:

Dvi