instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
TnbLNKnNSs, NhDLNKnNRd
answer:
LNKnN


question:
rlBoVyFsYqpmmQmelGBg, iKKaIyFsYqpmmWcrKn
answer:
yFsYqpmm


question:
mAajJAoZzLueyoLNGThw, QhZzLueyoLsVZGtgL
answer:

ZzLueyoL