With no explanation, label each line with "O", "other-chemicalthing", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
They
are
derivatives
of
xanthene
.
They:O
are:O
derivatives:O
of:O
xanthene:other-chemicalthing
.:O