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
length
of
the
area
code
for
landlines
is
either
2
or
3
digits
,
depending
on
the
population
density
of
the
area
.
The:O
length:O
of:O
the:O
area:O
code:O
for:O
landlines:O
is:O
either:O
2:O
or:O
3:O
digits:O
,:O
depending:O
on:O
the:O
population:O
density:O
of:O
the:O
area:O
.:O