https://blog.gongquiz.com/2021/12/03/%ed%98%91%eb%a0%a5%ec%a0%9csynergist%eb%a1%9c-%ec%9d%b4%ec%9a%a9%eb%90%98%eb%8a%94-%ea%b2%83%ec%9d%80-%ec%a2%85%ec%9e%90%ea%b8%b0%ec%82%ac-2004%eb%85%84-3%ec%9b%94-7%ec%9d%bc-%ea%b8%b0%ec%b6%9c/