Categorize the following products into either "essential" or "non-essential" categories.
Apple, Milk, Car, Dog
Essential: Milk, Apple
Non-essential: Car, Dog.
Complete the following task based on the instruction and optional input provided.### Instruction:
Categorize the following products into either "essential" or "non-essential" categories.

### Input:
Apple, Milk, Car, Dog

### Output:
Essential: Milk, Apple
Non-essential: Car, Dog.