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:
plSfJAktMfac, TCjYJAktlt
answer:
JAkt


question:
gfDDsblwUryUw, UWaRisblwUTqTM
answer:

sblwU