instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
mmDhYqPJC, qThYqxW
answer:
hYq


question:
eNuawupVqQ, RIawuplUIf
answer:
awup


question:
ErVrvCm, thVrvKVp
answer:

Vrv