instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
WlqGjLNrxXeUrKCZel, pDSsmNrxXeUrKCslBXBbRu
answer:
NrxXeUrKC


question:
ktABEFESAVHZkkY, uMjxiESAVHZkZgWUte
answer:
ESAVHZk


question:
JMzUBjdwxbKQRBFgDLUbFKh, XVVEFjdwxbKQRBFXzTXwRqgd
answer:

jdwxbKQRBF