instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
YCAyruPTTHWhCYaiXfIl, OETdzqAyruPTTHWgS
answer:
AyruPTTHW


question:
MvALRGKkpALcKdhTtnm, neMkRGKkpALcKdcaxnXEPxW
answer:
RGKkpALcKd


question:
KhgEMLfxcOuJdNOXiH, IMTgEMLfxcOMNTSj
answer:

gEMLfxcO