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 ":".
The
river
is
a
source
of
alluvial
gold
.
The:O
river:O
is:O
a:O
source:O
of:O
alluvial:O
gold:O
.:O