With no explanation, label each line with "O", "person-other", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
It
was
left
to
his
successor
,
Pope
Gregory
IX
,
to
insist
upon
their
accomplishment
.
It:O
was:O
left:O
to:O
his:O
successor:O
,:O
Pope:O
Gregory:person-other
IX:person-other
,:O
to:O
insist:O
upon:O
their:O
accomplishment:O
.:O