With no explanation, label each line with "product-other", "product-airplane", "O", "product-weapon", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting" or "art-writtenart" preceded by ":".
In
real
time
,
the
RPVs
relayed
the
information
to
the
RB-47
which
was
itself
using
ELINT
sensors
against
the
radar
and
SA-2
command
frequencies
.
In:O
real:O
time:O
,:O
the:O
RPVs:product-airplane
relayed:O
the:O
information:O
to:O
the:O
RB-47:product-airplane
which:O
was:O
itself:O
using:O
ELINT:product-other
sensors:product-other
against:O
the:O
radar:product-other
and:O
SA-2:product-weapon
command:O
frequencies:O
.:O