https://blog.faceutil.com/2017/03/21/%ec%9d%b8%ed%84%b0%eb%84%b7%ec%9c%bc%eb%a1%9c-%ec%97%b4%eb%9e%8c%ed%95%9c-%ed%94%8c%eb%9e%98%ec%8b%9c-%ed%8c%8c%ec%9d%bc-swf-%eb%8b%a4%ec%9a%b4%eb%a1%9c%eb%93%9c%ed%95%98%eb%8a%94-%eb%b0%a9%eb%b2%95-d/