user: Question: What is Lowest Rank, when Location is rio de janeiro, brazil, and when Current Seating Capacity is less than 78838?
Columns: ['Rank', 'Venue name', 'Highest attendance', 'Location', 'Current seating capacity']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1.0, 'Indianapolis Motor Speedway', '400,000', 'Speedway , Indiana , United States', 257325.0]
SQL:

assistant: SELECT MIN("Rank") FROM "Table" WHERE "Location" = 'rio de janeiro, brazil' AND "Current seating capacity" < 78838.0;