instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
yJRITYgVTSNsPjG, NSIdKYgVTSNmj
answer:
YgVTSN


question:
PQCjJwXurLeN, vsjJwXuOy
answer:
jJwXu


question:
wFeqOk, dBeqFP
answer:

eq