With no explanation, label each line with "product-airplane", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
It
served
in
the
reconnaissance
role
until
1992
,
when
it
received
Boeing
KC-135
Stratotankers
and
converted
to
an
air
refueling
mission
.
It:O
served:O
in:O
the:O
reconnaissance:O
role:O
until:O
1992:O
,:O
when:O
it:O
received:O
Boeing:product-airplane
KC-135:product-airplane
Stratotankers:product-airplane
and:O
converted:O
to:O
an:O
air:O
refueling:O
mission:O
.:O