Fantastic question! I have a secret love for problems like this - I always loved those puzzles in middle school/high school to figure out complicated pairings (usually it was something like students with different eye/hair color and favorite subjects and the clues would be "none of the students with brown hair like science" or "none of the students with green eyes also have black hair")
Anyway, I think you are missing the "!" symbol which means "not". I made a diagram here to help explain how I break it down. I am starting in the middle (or in the parentheses) and then evaluating outward. Does that help?