How many were written by Peter Winther?
CREATE TABLE "table1_20704243_3" (
  "series_num" real,
  "season_num" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "u_s_viewers_in_millions" text
);
SELECT COUNT("written_by") FROM "table1_20704243_3" WHERE "directed_by"='Peter Winther';