https://blog.faceutil.com/2020/05/26/%eb%a1%9c%ec%8a%a4%ec%bf%a8-%eb%a6%ac%ed%8a%b8-leet-2016-%ea%b8%b0%ec%b6%9c%eb%ac%b8%ec%a0%9c-%eb%b0%8f-%ed%91%9c%ec%a4%80%ec%a0%90%ec%88%98-%cf%89/