text: Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
  ### Context:
  CREATE TABLE table_17641206_4 (duration VARCHAR, written_by VARCHAR)
  ### Question:
  How many episodes  of 30 minutes were written by John Sullivan?
  ### Answer:
  SELECT COUNT(duration) FROM table_17641206_4 WHERE written_by = "John Sullivan"