User-Agent: *
Disallow: /z/

User-Agent: Googlebot
Disallow: /z/

User-Agent: Googlebot-Mobile
Disallow: /z/

User-Agent: Googlebot-Image
Disallow: /z/

User-Agent: Mediapartners-Google
Allow: /z/

User-agent: AdsBot-Google 
Allow: /z/