With no explanation, label each line with "O", "product-train", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
They
were
nicknamed
'
Black
Swans
'
(
'
schwarze
Schwäne
'
)
as
a
result
of
their
elegant
shape
.
They:O
were:O
nicknamed:O
':O
Black:product-train
Swans:product-train
':O
(:O
':O
schwarze:product-train
Schwäne:product-train
':O
):O
as:O
a:O
result:O
of:O
their:O
elegant:O
shape:O
.:O