With no explanation, label each line with "location-GPE", "art-film", "O", "location-other", "art-broadcastprogram", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
``
What
Happened
in
Vegas
``
prompted
Denison
's
probe
into
the
2017
mass
shooting
at
the
Mandalay
Bay
Resort
in
Las
Vegas
,
where
59
people
were
killed
,
for
a
second
documentary
.
``:O
What:art-film
Happened:art-film
in:art-film
Vegas:art-film
``:O
prompted:O
Denison:O
's:O
probe:O
into:O
the:O
2017:O
mass:O
shooting:O
at:O
the:O
Mandalay:location-other
Bay:location-other
Resort:location-other
in:O
Las:location-GPE
Vegas:location-GPE
,:O
where:O
59:O
people:O
were:O
killed:O
,:O
for:O
a:O
second:O
documentary:O
.:O