instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
HiEuutntEBpU, fdkqEuutntEBABdGZRND
answer:
EuutntEB


question:
EOacPYivmmUlYenynBqAwx, MoZWMOeXmUlYenynBEendWg
answer:
mUlYenynB


question:
MNrbMrAayIWyfHwhT, ygRODyalrAayIWyfHYztnBhG
answer:

rAayIWyfH