instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
UldKHMpUYADGfEUGcSon, nPHMpUYADGfEKqHCLPmL
answer:
HMpUYADGfE


question:
bVlwKYBYmcNq, hBlwKYBprL
answer:
lwKYB


question:
OLqjiUVQ, UDXqjiNZW
answer:

qji