With no explanation, label each line with "location-GPE", "O", "location-road/railway/highway/transit", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
The
Pittsburgh
Line
is
NS
's
principal
east–west
line
from
the
Northeast
to
the
Midwest
.
The:O
Pittsburgh:location-road/railway/highway/transit
Line:location-road/railway/highway/transit
is:O
NS:location-GPE
's:O
principal:O
east–west:O
line:O
from:O
the:O
Northeast:O
to:O
the:O
Midwest:O
.:O