[kmes]

Def not a jack russell...
Honestly I don't think even a mix.
I don't recognize the breed offhand. Could be a mixed breed but also perhaps an Italian breed not so common outside your country? Many of us are in the US and Canada so wouldn't be super familiar unless known over here.

 

[kmes]

Idk about ovcharka...
Granted I'm no expert on the breed and have never seen on in person, it's just that based on the pics I have seen I would expect a pup to be heavier boned, have a different muzzle, and perhaps also a different ear set... could be totally wrong though.

Regardless, ovcharka's are not a good fit for the vast majority of people. Not something to dive into based on looks alone.