With no explanation, label each line with "O", "location-mountain", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
An
alternative
route
follows
the
Ptarmigan
ridge
to
the
summit
along
a
steeper
and
rockier
path
.
An:O
alternative:O
route:O
follows:O
the:O
Ptarmigan:location-mountain
ridge:location-mountain
to:O
the:O
summit:O
along:O
a:O
steeper:O
and:O
rockier:O
path:O
.:O