instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
srPyjmTQhdFFMcQ, QQGBdtyjmTQhmfEy
answer:
yjmTQh


question:
sbQJFbUtmnKaEJePFPeRM, QzfvkdZbUtmnKaEJNrWD
answer:
bUtmnKaEJ


question:
ZcBttAeYMkWyKCDXNDlGRH, AgtjbPsnxHAeYMkWyKCDnAWZBZI
answer:

AeYMkWyKCD