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 ":".
About
500
ZSU-57-2s
survived
the
war
.
About:O
500:O
ZSU-57-2s:product-weapon
survived:O
the:O
war:O
.:O