With no explanation, label each line with "location-GPE", "O", "location-other", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
For
centuries
,
shaped
at
cultural
boundaries
between
East
and
West
,
a
powerful
medieval
kingdom
–
later
renamed
the
Serbian
Empire
–
occupied
much
of
the
Balkans
.
For:O
centuries:O
,:O
shaped:O
at:O
cultural:O
boundaries:O
between:O
East:O
and:O
West:O
,:O
a:O
powerful:O
medieval:O
kingdom:O
–:O
later:O
renamed:O
the:O
Serbian:location-GPE
Empire:O
–:O
occupied:O
much:O
of:O
the:O
Balkans:location-other
.:O