With no explanation, label each line with "location-GPE", "O", "other-law", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
From
the
Treaty
of
Nerchinsk
(
1689
)
to
the
Treaty
of
Aigun
(
1858
)
its
lower
course
was
officially
part
of
the
border
between
Russia
and
China
,
although
the
border
was
not
clearly
marked
and
the
area
rarely
visited
.
From:O
the:O
Treaty:other-law
of:other-law
Nerchinsk:other-law
(:O
1689:O
):O
to:O
the:O
Treaty:other-law
of:other-law
Aigun:other-law
(:O
1858:O
):O
its:O
lower:O
course:O
was:O
officially:O
part:O
of:O
the:O
border:O
between:O
Russia:location-GPE
and:O
China:location-GPE
,:O
although:O
the:O
border:O
was:O
not:O
clearly:O
marked:O
and:O
the:O
area:O
rarely:O
visited:O
.:O