deb http://mirrors.ustc.edu.cn/debian/ jessie main contrib non-free deb-src http://mirrors.ustc.edu.cn/debian/ jessie main contrib non-free deb http://mirrors.ustc.edu.cn/debian/ jessie-updates main contrib non-free deb-src http://mirrors.ustc.edu.cn/debian/ jessie-updates main contrib non-free deb http://mirrors.ustc.edu.cn/debian/ jessie-backports main contrib non-free deb-src http://mirrors.ustc.edu.cn/debian/ jessie-backports main contrib non-free deb http://mirrors.ustc.edu.cn/debian-security/ jessie/updates main contrib non-free deb-src http://mirrors.ustc.edu.cn/debian-security/ jessie/updates main contrib non-free