What is the highest series number of the episode "Til Death do us part-and make it soon"?
CREATE TABLE "table1_23916272_6" (
  "series_num" real,
  "season_num" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text
);
SELECT MAX("series_num") FROM "table1_23916272_6" WHERE "title"='\"Til Death Do Us Part-And Make It Soon\"';