What is the maximum season number for the episode written by Jonathan Greene?
CREATE TABLE "table1_23225927_1" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" real,
  "u_s_viewers_millions" text
);
SELECT MAX("no_in_season") FROM "table1_23225927_1" WHERE "written_by"='Jonathan Greene';