With no explanation, label each line with "O", "product-weapon", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
ships
were
fitted
with
four
twin-gun
mounts
for
DShK
machine
guns
.
The:O
ships:O
were:O
fitted:O
with:O
four:O
twin-gun:O
mounts:O
for:O
DShK:product-weapon
machine:product-weapon
guns:product-weapon
.:O