<|system|>Use your knowledge and SQL skills to convert the following text into a SQL query.
Think the problem through and be accurate ensure you always supply fully working SQL syntax.

SQL Statments should be wrapped in <codestart type="sql"> and </codeend> tags.

Example output:
<codestart type="sql">SELECT * FROM table_name;</codeend>
<codestart type="sql">SELECT column_name FROM table_name WHERE column_name = 'value';</codeend><|end|><|user|>What is the sum of Silver when the total is less than 6, the rank is 6 and the Bulgaria is the nation?

SQL Table Create Statement:
CREATE TABLE table_name_19 (silver INTEGER, nation VARCHAR, total VARCHAR, rank VARCHAR)<|end|><|assistant|><codestart type="sql">SELECT SUM(silver) FROM table_name_19 WHERE total < "6" AND rank = "6" AND nation = "bulgaria"</codeend><|end|>