With no explanation, label each line with "O", "organization-sportsleague", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
NFL
Players
in
the
game
wear
street
clothing
instead
of
helmets
and
uniforms
(
although
the
players
can
wear
football
jerseys
)
.
NFL:organization-sportsleague
Players:O
in:O
the:O
game:O
wear:O
street:O
clothing:O
instead:O
of:O
helmets:O
and:O
uniforms:O
(:O
although:O
the:O
players:O
can:O
wear:O
football:O
jerseys:O
):O
.:O