instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
XYnCjAWPHHJ, gmCjAWPHpmwVsm
answer:
CjAWPH


question:
CiTNsbepy, DFNsbeZl
answer:
Nsbe


question:
zRwQdelc, UdAUwQdejhe
answer:

wQde