how many episodes has been directed by Mark K. Samuels ?
CREATE TABLE "table1_2226817_12" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" text
);
SELECT COUNT("no_in_series") FROM "table1_2226817_12" WHERE "directed_by"='Mark K. Samuels';