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 ":".
On
the
back
,
they
are
stamped
:
``
Photogr
.
On:O
the:O
back:O
,:O
they:O
are:O
stamped:O
::O
``:O
Photogr:O
.:O