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 ":".
139
units
were
built
,
but
some
were
later
converted
to
and
units
.
139:O
units:O
were:O
built:O
,:O
but:O
some:O
were:O
later:O
converted:O
to:O
and:O
units:O
.:O