instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
tftBHoDOYxCoTHVf, qhHoDOYxfUU
answer:
HoDOYx


question:
RyaNyUvXAaZHLXUtYuz, CkbsWxZyUvXAaZHLXJJzugDy
answer:
yUvXAaZHLX


question:
XLmHlTBzXGMix, YhlTBzXGMOfIR
answer:

lTBzXGM