CREATE TABLE table_name_51 (gold INTEGER, bronze VARCHAR(255), nation VARCHAR(255), silver VARCHAR(255), total VARCHAR(255))
Silver larger than 0, and a Total smaller than 3, and a Nation of bulgaria, and a Bronze smaller than 0 had what sum of gold?
    
SQL: SELECT SUM(gold) FROM table_name_51 WHERE silver > 0 AND total < 3 AND nation = "bulgaria" AND bronze < 0