user: Question: What is the total number of bronze medals for teams with less than 0 silver?
Columns: ['Rank', 'Nation', 'Gold', 'Silver', 'Bronze', 'Total']
Types: ['real', 'text', 'real', 'real', 'real', 'real']
Sample row: [1.0, 'United States (host nation)', 78.0, 82.0, 79.0, 239.0]
SQL:

assistant: SELECT SUM("Bronze") FROM "Table" WHERE "Silver" < 0.0;