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 ":".
On
9
April
,
the
port
of
El
Callao
was
placed
under
blockade
.
On:O
9:O
April:O
,:O
the:O
port:O
of:O
El:location-GPE
Callao:location-GPE
was:O
placed:O
under:O
blockade:O
.:O