instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
OhMVLbQhBxEaOZY, iDVLbQhBxBiiD
answer:
VLbQhBx


question:
bUcuzFgsdfojVR, IdcuzFgsdMRgtMA
answer:
cuzFgsd


question:
LGrPTZAiNOJkHHNyqZ, sMLwxQLZAiNOJkWSNXKwV
answer:

ZAiNOJk