instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
HKqfdEvqDuGhWByFlzIEeYh, VVaZfkLCMuGhWByFlzIOZaXbMCA
answer:
uGhWByFlzI


question:
oGaGjsaKsUpLQAg, iDGjsaKsUoYGuta
answer:
GjsaKsU


question:
IvMVZDyncPfBRI, nlwRDOSZDyncPfBNRWT
answer:

ZDyncPfB