CREATE TABLE "table1_21328899_1" (
  "series_num" real,
  "season_num" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text
);

Question: When "i feel good" is the title and joe sachs is the writer how many series numbers are there?
SQL: SELECT COUNT("series_num") FROM "table1_21328899_1" WHERE "written_by"='Joe Sachs' AND "title"='\"I Feel Good\"';