instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
JAfPtjqqUYMD, cpXItjqqFN
answer:
tjqq


question:
SeXNqRAbKdLuWXgb, npsIWRAbKdLuUWSbvuS
answer:
RAbKdLu


question:
mGjSQdEWtBaqDyAv, lLyGQdEWtBfST
answer:

QdEWtB