With no explanation, label each line with "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport", "building-hospital" or "building-hotel" preceded by ":".
Its
walls
are
and
thicker
.
Its:O
walls:O
are:O
and:O
thicker:O
.:O