https://purengom.com/2010/07/27/%ed%8b%b0%ec%8a%a4%ed%86%a0%eb%a6%ac-iphone-%ec%95%b1%ec%9d%80-%ec%96%b8%ec%a0%9c%eb%82%98-40-%ed%98%b8%ed%99%98-%eb%90%a0%ea%b9%8c%ec%9a%94/