Given a list of cities, classify each city as either a developed or developing city.
Sydney, Rio de Janeiro, Cairo
- Sydney: Developed city
- Rio de Janeiro: Developing city
- Cairo: Developing city
Complete the following task based on the instruction and optional input provided.### Instruction:
Given a list of cities, classify each city as either a developed or developing city.

### Input:
Sydney, Rio de Janeiro, Cairo

### Output:
- Sydney: Developed city
- Rio de Janeiro: Developing city
- Cairo: Developing city