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
Sherman
was
a
relatively
inexpensive
,
easy
to
maintain
and
produce
combat
system
.
The:O
Sherman:product-weapon
was:O
a:O
relatively:O
inexpensive:O
,:O
easy:O
to:O
maintain:O
and:O
produce:O
combat:O
system:O
.:O