instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
xeKSiBafhOWBbYwlGaQ, GUfIsKgafhOWBbYiFWnptAt
answer:
afhOWBbY


question:
wrVsKN, mOVsWo
answer:
Vs


question:
VqdQMygIdoGKzU, PuKQgIdoGKVvQLO
answer:

gIdoGK