In the list of tokens, identify 'Person', 'Location', and 'Organisation' and label each accordingly. If the entity spans multiple tokens, use the prefix B-PER, B-LOC, or B-ORG for the first token, and I-PER, I-LOC, or I-ORG for the subsequent tokens of that entity. The beginning of each separate entity should always be labeled with a B-PER, B-LOC, or B-ORG prefix. If the token does not fit into any of the three named categories, or is not a named entity, label it as 'O'. Each line should contain one token and its corresponding label, separated by a colon. Do not combine tokens on your own. The format for each line should be: 'token:label'.

Text: San
Franciscans
William
Oberndorf
and
Helen
Schwab
each
gave
about
$
1.5
million
and
20
other
people
gave
at
least
$
1
million
apiece
.
Answer: 
San:B-LOC
Franciscans:I-LOC
William:B-PER
Oberndorf:I-PER
and:O
Helen:B-PER
Schwab:I-PER
each:O
gave:O
about:O
$:O
1.5:O
million:O
and:O
20:O
other:O
people:O
gave:O
at:O
least:O
$:O
1:O
million:O
apiece:O
.:O