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
rapid
motion
,
combined
with
the
presence
of
an
unusually
hostile
Saharan
Air
Layer
,
prevented
tropical
cyclogenesis
for
several
days
.
Its:O
rapid:O
motion:O
,:O
combined:O
with:O
the:O
presence:O
of:O
an:O
unusually:O
hostile:O
Saharan:O
Air:O
Layer:O
,:O
prevented:O
tropical:O
cyclogenesis:O
for:O
several:O
days:O
.:O