With no explanation, label each line with "location-GPE", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
Before
the
gold
rush
,
Maiden
was
the
largest
city
in
central
Montana
.
Before:O
the:O
gold:O
rush:O
,:O
Maiden:location-GPE
was:O
the:O
largest:O
city:O
in:O
central:O
Montana:location-GPE
.:O