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 ":".
The
aircraft
crashed
into
a
hill
approximately
500
m
(
1,600
ft
)
high
,
approximately
north
of
the
airport
at
about
16:23
.
The:O
aircraft:O
crashed:O
into:O
a:O
hill:O
approximately:O
500:O
m:O
(:O
1,600:O
ft:O
):O
high:O
,:O
approximately:O
north:O
of:O
the:O
airport:O
at:O
about:O
16:23:O
.:O