With no explanation, label each line with "O", "product-food", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
It
is
unclear
when
the
old-fashioned
doughnut
itself
was
invented
,
but
this
very
likely
occurred
``
after
''
the
cake
doughnut
was
invented
.
It:O
is:O
unclear:O
when:O
the:O
old-fashioned:O
doughnut:product-food
itself:O
was:O
invented:O
,:O
but:O
this:O
very:O
likely:O
occurred:O
``:O
after:O
'':O
the:O
cake:O
doughnut:product-food
was:O
invented:O
.:O