What is the total of the River Mile in Greenup, Kentucky?
CREATE TABLE "downstream_pittsburgh_to_olmsted" (
  "locks_dam" text,
  "location_l" text,
  "river_mile" real,
  "lock_side" text,
  "lock_lift_drop_in_feet" text,
  "pool_length_miles" text
);
SELECT SUM("river_mile") FROM "downstream_pittsburgh_to_olmsted" WHERE "location_l"='greenup, kentucky';