https://blog.gongquiz.com/2022/11/28/%eb%8b%a4%ec%9d%8c-%ea%b7%b8%eb%a6%bc%ea%b3%bc-%ea%b0%99%ec%9d%b4-%ec%a0%95%ec%a0%84-%ec%9a%a9%eb%9f%89-c1-c2%eb%a5%bc-%eb%b3%91%eb%a0%ac%eb%a1%9c-%ec%a0%91%ec%86%8d%ed%95%98%ec%98%80%ec%9d%84/