Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_19 (silver INTEGER, nation VARCHAR, total VARCHAR, rank VARCHAR)
### Question:
What is the sum of Silver when the total is less than 6, the rank is 6 and the Bulgaria is the nation?
### Answer:
SELECT SUM(silver) FROM table_name_19 WHERE total < "6" AND rank = "6" AND nation = "bulgaria"