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
reports
were
classified
Top
Secret
,
they
had
very
limited
distribution
,
and
the
authors
were
not
allowed
to
keep
copies
.
The:O
reports:O
were:O
classified:O
Top:O
Secret:O
,:O
they:O
had:O
very:O
limited:O
distribution:O
,:O
and:O
the:O
authors:O
were:O
not:O
allowed:O
to:O
keep:O
copies:O
.:O