instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
OjQHcFUCflYUptUPqYKVomn, GXHcFUCflYUpSSTrQ
answer:
HcFUCflYUp


question:
xQcYRVFFqrVAMsBm, VErcKZvcYRVFFqzKo
answer:
cYRVFFq


question:
tGBRASi, QABRAtL
answer:

BRA