user: Question: On how many different dates did the episode directed by Marcos Siega and written by Scott Buck air for the first time?
Columns: ['No. in series', 'No. in season', 'Title', 'Directed by', 'Written by', 'Original air date', 'U.S. viewers (millions)']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: [37.0, 1.0, '"Living the Dream"', 'Marcos Siega', 'Clyde Phillips', 'September27,2009', '1.9']
SQL:

assistant: SELECT COUNT("Original air date") FROM "Table" WHERE "Directed by" = 'Marcos Siega' AND "Written by" = 'Scott Buck';