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 ":".
Some
of
them
went
back
to
Socialist
Bulgaria
and
became
highly
placed
officials
there
.
Some:O
of:O
them:O
went:O
back:O
to:O
Socialist:location-GPE
Bulgaria:location-GPE
and:O
became:O
highly:O
placed:O
officials:O
there:O
.:O