With no explanation, label each line with "art-music", "O", "person-artist/author", "art-broadcastprogram", "art-film", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
They
subsequently
worked
with
Spears
on
her
fifth
studio
album
,
``
Blackout
``
,
for
which
they
collaborated
with
Spears
on
four
songs
:
the
hit
single
,
``
Piece
of
Me
``
,
``
Radar
``
,
``
Freakshow
``
and
``
Toy
Soldier
``
;
and
again
on
her
2008
follow-up
album
``
Circus
``
,
for
which
they
produced
the
songs
``
Unusual
You
``
,
``
Phonography
``
and
``
Trouble
``
,
the
latter
two
appeared
only
as
bonus
tracks
.
They:O
subsequently:O
worked:O
with:O
Spears:person-artist/author
on:O
her:O
fifth:O
studio:O
album:O
,:O
``:O
Blackout:art-music
``:O
,:O
for:O
which:O
they:O
collaborated:O
with:O
Spears:person-artist/author
on:O
four:O
songs:O
::O
the:O
hit:O
single:O
,:O
``:O
Piece:art-music
of:art-music
Me:art-music
``:O
,:O
``:O
Radar:art-music
``:O
,:O
``:O
Freakshow:art-music
``:O
and:O
``:O
Toy:art-music
Soldier:art-music
``:O
;:O
and:O
again:O
on:O
her:O
2008:O
follow-up:O
album:O
``:O
Circus:art-music
``:O
,:O
for:O
which:O
they:O
produced:O
the:O
songs:O
``:O
Unusual:art-music
You:art-music
``:O
,:O
``:O
Phonography:art-music
``:O
and:O
``:O
Trouble:art-music
``:O
,:O
the:O
latter:O
two:O
appeared:O
only:O
as:O
bonus:O
tracks:O
.:O