one of my favorite juices, I love both pineapple and apple juice and this combination with the mint is just perfect, you can play around with the ratio for different results based on what you like more (apples/pineapples).
A thing to note about how to prep the pineapple, let it sit on it side in the refrigerator for half an hour before you cut it, this would let all the sweetness which captured at the bottom of the pineapple spread throughout, and give you much more flavorful juice.
2 granny smith Apple
4 tbsp Mint (finely chopped)
1 oz Lime juice
Juice, mix and drink.