https://blog.gongquiz.com/2021/04/08/%ea%b0%95%ec%97%90%ec%84%9c-%ec%a0%81%ec%97%b4%ec%b7%a8%ec%84%b1red-shortness%ec%9d%98-%ec%a3%bc-%ec%9b%90%ec%9d%b8%ec%9d%80-%ec%a0%9c%ec%84%a0%ea%b8%b0%eb%8a%a5%ec%9e%a5-2004%eb%85%84-7/