With no explanation, label each line with "O", "organization-sportsleague", "event-sportsevent", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
FIFA
World
Cup
referees
are
FIFA
international
referees
who
officiate
at
the
FIFA
World
Cup
matches
.
FIFA:event-sportsevent
World:event-sportsevent
Cup:event-sportsevent
referees:O
are:O
FIFA:organization-sportsleague
international:O
referees:O
who:O
officiate:O
at:O
the:O
FIFA:event-sportsevent
World:event-sportsevent
Cup:event-sportsevent
matches:O
.:O