What is the quantity when the DRG was E 62 01–E 62 05?
CREATE TABLE "electric_locomotives" (
  "class" text,
  "drg_number_s" text,
  "quantity" real,
  "year_s_of_manufacture" text,
  "type" text
);
SELECT COUNT("quantity") FROM "electric_locomotives" WHERE "drg_number_s"='e 62 01–e 62 05';