I've also seen another way of saying the phrase "I don't know", which is "Fuck if I know".
"I don't give a fuck" means "I don't care", that is, what "you" say is not important to me. =)
The English ones? Here's another expression: "I don't give a fuck what you think and say."
Am I the only one here who doesn't get the idea of what this discussion is about? =)