user: Question: What is the minimum number of perfect 40s?
Columns: ['Rank by average', 'Place', 'Couple', 'Perfect 40s', 'Total', 'Number of dances', 'Season', 'Average']
Types: ['real', 'text', 'text', 'real', 'real', 'real', 'real', 'text']
Sample row: [1.0, '2nd', 'Natasza Urbańska & Ján Kliment', 11.0, 666.0, 17.0, 10.0, '39.18']
SQL:

assistant: SELECT MIN("Perfect 40s") FROM "Table";