How many categories of new entries this round are there for the fourth round proper? 
CREATE TABLE "calendar" (
  "round" text,
  "main_date" text,
  "number_of_fixtures" real,
  "clubs" text,
  "new_entries_this_round" text,
  "prize_money" text,
  "player_of_the_round" text
);
SELECT COUNT("new_entries_this_round") FROM "calendar" WHERE "round"='Fourth Round Proper';