user: Question: What is the sum of the gold medals of the total nation, which has more than 19 silver medals?
Columns: ['Rank', 'Nation', 'Gold', 'Silver', 'Bronze', 'Total']
Types: ['text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['1', 'Soviet Union', 9.0, 5.0, 2.0, 16.0]
SQL:

assistant: SELECT SUM("Gold") FROM "Table" WHERE "Nation" = 'total' AND "Silver" > 19.0;