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:
JXnHYuZvAYK, zhUYuZvASGhd
answer:
YuZvA


question:
JhXZZCamQbSRBfdzvl, qhHMGCZCamQbSAkWX
answer:

ZCamQbS