instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
YKpdeJQhzyYiPoODACUu, mjmnIlCehzyYiPoOzZ
answer:
hzyYiPoO


question:
OyrqfQQnzOFUzrkDM, iBkQQnzOFewhjvO
answer:
QQnzOF


question:
rZFfcCYjgf, YkpcCYjYbrK
answer:

cCYj