With no explanation, label each line with "O", "organization-government/governmentagency", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
In
1937
the
US
Post
Office
issued
a
series
of
commemorative
stamp
issues
honoring
various
Army
and
Navy
heroes
.
In:O
1937:O
the:O
US:organization-government/governmentagency
Post:organization-government/governmentagency
Office:organization-government/governmentagency
issued:O
a:O
series:O
of:O
commemorative:O
stamp:O
issues:O
honoring:O
various:O
Army:O
and:O
Navy:O
heroes:O
.:O