instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
OYERnjubLFovtcS, FngzQJVGERnjubLFafmzq
answer:
ERnjubLF


question:
skZGHS, HsZGge
answer:
ZG


question:
xYbZQIHmstSpzVrRPpWl, RTWJvvoHmstSpzznees
answer:

HmstSpz