https://blog.gongquiz.com/2022/08/22/%eb%b0%98%ec%a7%80%eb%a6%84-40%e3%8e%9d%ec%9d%b8-%ec%9b%90%ed%86%b5-%ec%86%8d%ec%97%90-%eb%ac%bc%ec%9d%84-%eb%8b%b4%ec%95%84-30rpm%ec%9c%bc%eb%a1%9c-%ed%9a%8c%ec%a0%84%ec%8b%9c%ed%82%ac-%eb%95%8c/