Multiple entry visa. I have a Netherlands passport.

Hi,
I am planning on arriving in HK for 3 days, then I travel to Shanghai for less than 72 hours and then travel back to Hong Kong for my final flight back home.

As a Dutch national can I travel to both HK and Shanghai without an entry permit? Will there be an issue because I will be entering and exiting HK twice during a short period of time?

Thanks!