#Allow non-bad bots to index site.
User-agent: *
DisAllow:

#Stop the following specific bots from scanning site and limit scanning to 20seconds intervals.
User-Agent: AhrefsBot
Disallow: /
Crawl-Delay: 20
User-Agent: SemrushBot
Disallow: /
Crawl-Delay: 20
User-Agent: Semrushbot-SA
Disallow: /
Crawl-Delay: 20
User-Agent: Semrushbot-SI
Disallow: /
Crawl-Delay: 20
User-Agent: Yandex
Disallow: /
Crawl-Delay: 20
User-Agent: BingBot
Disallow: /
Crawl-Delay: 20

#Need to add a site map.