instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
biAihydBoNlzR, IAloNhydBolwUz
answer:
hydBo


question:
LeHzcEFc, WFzcExvJ
answer:
zcE


question:
HJaCsHobDMQIlfdQZtNTWc, OwiMJobDMQIlfdQPXCLv
answer:

obDMQIlfdQ