instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
oHoJrr, YAoJSq
answer:
oJ


question:
ocjsZZfSBBopDtgWUT, rWmgzsZZfSBBoGWQ
answer:
sZZfSBBo


question:
xHsVgHGoLUe, VMECgHGoLovWBK
answer:

gHGoL