user: Question: How many chapters did elmer clifton direct?
Columns: ['Number', 'Serial Title', 'Year', 'Chapters', 'Genre', 'Director', 'Cast']
Types: ['real', 'text', 'real', 'real', 'text', 'text', 'text']
Sample row: [1.0, 'Jungle Menace', 1937.0, 15.0, 'Jungle', 'Harry L. Fraser and George Melford', 'Frank Buck']
SQL:

assistant: SELECT SUM("Chapters") FROM "Table" WHERE "Director" = 'elmer clifton';