Functional requirements:

$-$ Internal users are Headquarters and remote office

$-$ Internal user do DNS resolution on $202\mathrm{.}22\mathrm{.}1\mathrm{.}3$ and can access corporate web and internal mail.

$-$ Email between Internal and Internet transit via Email relay for virus scan.

$-$ The internal DNS resolve to ISP DNS for unknown zones.

$-$ External web, relay email handles all Internet user access including DNS resolve.

$-$ All internal users can access web on $80/443$

$-$ A "Bad guy" is $12\mathrm{.}55\mathrm{.}55\mathrm{.}55-$ prevent any access

$-$ All firewalls are statefull, return traffic inspection is not required.

How many rule sets should be developed?

$1?2?4?6?8?10?12?300\mathrm{.}5?$ more?

Please write all necessary rules and answer how many rule sets should be developed! :)