What is the amount of US open runner-up score?
CREATE TABLE "grand_slam_7_finals_3_titles_4_runner_up" (
  "outcome" text,
  "year" real,
  "championship" text,
  "surface" text,
  "opponent_in_final" text,
  "score_in_final" text
);
SELECT COUNT("score_in_final") FROM "grand_slam_7_finals_3_titles_4_runner_up" WHERE "championship"='US Open' AND "outcome"='Runner-up';