Translation:I like only purple! Not blue and not red, only purple.
In English, "and" is hardly ever used between two negative structures, so I omitted it, and, alas! my answer was rejected. An even better answer would be "I only like purple - not blue or red, but purple!" But I know DL is just incapable of going that far. Look, guys, you'd better not use sentences with poorly worded translations at all, than impose such translations on learners.