With no explanation, label each line with "O", "location-other", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
After
wintering
,
in
1644
Poyarkov
pushed
down
the
Zeya
and
became
the
first
Russian
to
reach
the
Amur
River
.
After:O
wintering:O
,:O
in:O
1644:O
Poyarkov:O
pushed:O
down:O
the:O
Zeya:location-other
and:O
became:O
the:O
first:O
Russian:O
to:O
reach:O
the:O
Amur:location-other
River:location-other
.:O