What is the sum of # Of Candidates, when # of Constituency Votes is less than 25,643,309, when Leader is Masayoshi Ōhira, and when Election is before 1979?
CREATE TABLE "general_election_results" (
  "election" real,
  "leader" text,
  "num_of_candidates" real,
  "num_of_constituency_votes" real,
  "pct_of_constituency_vote" text
);
SELECT SUM("num_of_candidates") FROM "general_election_results" WHERE "num_of_constituency_votes"<'25,643,309' AND "leader"='masayoshi ōhira' AND "election"<1979;