With no explanation, label each line with "location-GPE", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
It
is
surrounded
on
three
sides
by
the
Canada
–
United
States
border
.
It:O
is:O
surrounded:O
on:O
three:O
sides:O
by:O
the:O
Canada:location-GPE
–:O
United:location-GPE
States:location-GPE
border:O
.:O