Preheat oven to 375. Place rack in lowest position in oven. In large bowl toss apples with 3 tablespoons of flour and 1 teaspoon of cinnamon. In heavy saucepan combine sweeted condensed milk and carmels. Over medium heat, cook and stir till melted and mixture is smooth. Immediately toss carmel mixture with apples. Spoon in to pastry shell. TOPPINGIn small bowl, combine remaining quarter cup flour, sugar and remaining half teaspoon of cinnamon. Cut in margarine till mixture is crumbly stir in nuts and sprinkle over pie. Bake 35 minutes; coover loosley with aluminum foil to prevent overbrowning. Bake 10 minutes longer. Cool Serve warm refrigerate leftovers. ----