With no explanation, label each line with "O", "person-politician", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
Senators
Arlen
Specter
and
Bob
Casey
,
Jr
.
sent
a
joint
letter
to
President
Barack
Obama
,
seeking
support
for
Amtrak
service
between
the
two
cities
.
Senators:O
Arlen:person-politician
Specter:person-politician
and:O
Bob:person-politician
Casey:person-politician
,:person-politician
Jr:person-politician
.:person-politician
sent:O
a:O
joint:O
letter:O
to:O
President:O
Barack:person-politician
Obama:person-politician
,:O
seeking:O
support:O
for:O
Amtrak:O
service:O
between:O
the:O
two:O
cities:O
.:O