With no explanation, label each line with "location-GPE", "O", "person-other", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
During
this
period
,
three
of
Russia
's
most
notorious
rebels
,
Stenka
Razin
,
Kondraty
Bulavin
and
Emelian
Pugachev
,
were
Don
Cossacks
.
During:O
this:O
period:O
,:O
three:O
of:O
Russia:location-GPE
's:O
most:O
notorious:O
rebels:O
,:O
Stenka:person-other
Razin:person-other
,:O
Kondraty:person-other
Bulavin:person-other
and:O
Emelian:person-other
Pugachev:person-other
,:O
were:O
Don:O
Cossacks:O
.:O