instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
umXfmRnUgALpFAqBaKfNfo, aOAXWnUgALpFAqBmNpTCdj
answer:
nUgALpFAqB


question:
gfDDsblwUryUw, UWaRisblwUTqTM
answer:
sblwU


question:
xCcMptCsdewFFFk, QShFbCsdewFUGl
answer:

CsdewF