instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
XpFCxFOgTTNCnQzMnVPV, FMqzdOwgTTNCnQzedorxVPe
answer:
gTTNCnQz


question:
CxwZWv, mkwZgM
answer:
wZ


question:
leFnGFzFpPXyGjbL, xOzzFpPXyerfg
answer:

zFpPXy