instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
cUCQXEFSgRZjK, RYdvUQXEFSgRZVlwx
answer:
QXEFSgRZ


question:
AedXEOrEgvnzF, TVTEOrEgvxKuJgv
answer:
EOrEgv


question:
jSUeawhXyOWZoEmGi, EjuiHwhXyOWwELS
answer:

whXyOW