github 推送时can't be established.

http://www.xuebuyuan.com/2095099.html   

飞凡@FANZ /e/learngit (master)
$ git push origin master
The authenticity of host 'github.com (192.30.252.128)' can't be established.
RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
Are you sure you want to continue connecting (yes/no)? yes   

//不能直接回车，要填写yes