User-agent: Googlebot
Disallow:/a/

User-agent: baiduspider
Disallow:/a/

User-agent: Nutch
Disallow:/a/

User-agent: msnbot
Disallow:/a/

User-agent: Slurp
Disallow:/a/

User-agent: Sogou
Disallow:/a/

User-agent: Sosospider  
Disallow:/a/

User-agent: *
Disallow: /