Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_26611 ( "No. in series" real, "No. in season" real, "Title" text, "Directed by" text, "Written by" text, "Original air date" text, "U.S. viewers (millions)" text )

### Question ###
On how many different dates did the episode directed by Marcos Siega and written by Scott Buck air for the first time?

### Accurate SQL ###

SELECT COUNT("Original air date") FROM table_26611 WHERE "Directed by" = 'Marcos Siega' AND "Written by" = 'Scott Buck'