user: Question: How many episodes had celebrity guest stars Frank Skinner and Lee Mack?
Columns: ['Episode', 'Stage', 'Celebrities', 'Directed and produced by', 'Original airdate', 'Viewers (overnight estimates)']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '"England to Turkey"', 'Frank Skinner and Lee Mack', 'Rupert Miles', '13October2009', '4.2million']
SQL:

assistant: SELECT COUNT("Episode") FROM "Table" WHERE "Celebrities" = 'Frank Skinner and Lee Mack';