instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
JAGuNgaUudP, eojvKNgaUuQg
answer:
NgaUu


question:
apGMPThLTCw, LvMPThYW
answer:
MPTh


question:
oWScdRUz, wKIcdRjP
answer:

cdR