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 ":".
In
comparison
to
the
two
other
major
groups
or
marine
or
sea
mammals
,
cetaceans
and
sirenians
,
pinnipeds
are
a
relatively
younger
group
having
appeared
about
24
to
38
million
years
ago
and
are
still
able
to
return
on
land
to
breed
.
In:O
comparison:O
to:O
the:O
two:O
other:O
major:O
groups:O
or:O
marine:O
or:O
sea:O
mammals:O
,:O
cetaceans:O
and:O
sirenians:O
,:O
pinnipeds:O
are:O
a:O
relatively:O
younger:O
group:O
having:O
appeared:O
about:O
24:O
to:O
38:O
million:O
years:O
ago:O
and:O
are:O
still:O
able:O
to:O
return:O
on:O
land:O
to:O
breed:O
.:O