instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
mCxQTIaXN, mWQTIaxzPT
answer:
QTIa


question:
cZSEmdgP, YsSEmEIM
answer:
SEm


question:
juhBsENKXPuu, JLhBsENAJh
answer:

hBsEN