How many words are there in rusyn for the bulgarian word купува (kupuva)?
CREATE TABLE "other_slavic_languages" (
  "english_word" text,
  "slovak" text,
  "czech" text,
  "rusyn" text,
  "ukrainian" text,
  "belarusian" text,
  "polish" text,
  "serbo_croatian" text,
  "bulgarian" text
);
SELECT COUNT("rusyn") FROM "other_slavic_languages" WHERE "bulgarian"='купува (kupuva)';