With no explanation, label each line with "O", "event-sportsevent", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
As
a
racehorse
he
was
a
successful
sprinter
but
not
a
champion
,
recording
his
biggest
success
when
he
won
the
Richmond
Stakes
as
a
two-year-old
in
1950
.
As:O
a:O
racehorse:O
he:O
was:O
a:O
successful:O
sprinter:O
but:O
not:O
a:O
champion:O
,:O
recording:O
his:O
biggest:O
success:O
when:O
he:O
won:O
the:O
Richmond:event-sportsevent
Stakes:event-sportsevent
as:O
a:O
two-year-old:O
in:O
1950:O
.:O