With no explanation, label each line with "product-other", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
It
featured
two
coaxial
main
rotors
,
a
single-seat
open
cockpit
without
a
windshield
,
skid-type
landing
gear
and
two
twin-cylinder
,
air-cooled
,
two-stroke
,
dual-ignition
Hirth
2706
engines
.
It:O
featured:O
two:O
coaxial:O
main:O
rotors:O
,:O
a:O
single-seat:O
open:O
cockpit:O
without:O
a:O
windshield:O
,:O
skid-type:O
landing:O
gear:O
and:O
two:O
twin-cylinder:O
,:O
air-cooled:O
,:O
two-stroke:O
,:O
dual-ignition:O
Hirth:product-other
2706:product-other
engines:O
.:O