With no explanation, label each line with "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport", "building-hospital" or "building-hotel" preceded by ":".
It
was
the
first
tram
in
the
world
in
regular
service
that
was
run
with
electricity
served
by
an
overhead
line
with
pantograph
current
collectors
.
It:O
was:O
the:O
first:O
tram:O
in:O
the:O
world:O
in:O
regular:O
service:O
that:O
was:O
run:O
with:O
electricity:O
served:O
by:O
an:O
overhead:O
line:O
with:O
pantograph:O
current:O
collectors:O
.:O