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 ":".
By
2001
,
the
firm
employed
more
than
600
attorneys
,
reaching
its
peak
in
size
.
By:O
2001:O
,:O
the:O
firm:O
employed:O
more:O
than:O
600:O
attorneys:O
,:O
reaching:O
its:O
peak:O
in:O
size:O
.:O