What is the sum of the area for the bahawalnagar district with a population more than 134,936?
CREATE TABLE "punjab" (
  "serial_no" real,
  "district" text,
  "headquartered_city" text,
  "city_population_2009" real,
  "city_area_km_2" real
);
SELECT SUM("city_area_km_2") FROM "punjab" WHERE "district"='bahawalnagar district' AND "city_population_2009">'134,936';