instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
xMxyohPBlJIEBqghiMdBQPwq, xsBlJIEBqghlMosK
answer:
BlJIEBqgh


question:
HKqfdEvqDuGhWByFlzIEeYh, VVaZfkLCMuGhWByFlzIOZaXbMCA
answer:
uGhWByFlzI


question:
ZLOYoE, zbOYhJ
answer:

OY