FIFO Page Replacement Program

I need a Python program that implements memory management using the First In First Out (FIFO) page replacement approach. The program should handle page references and manage memory efficiently.

Requirements:
- Implement FIFO page replacement algorithm
- Prompt for correct input on invalid page references
- Include line-by-line comments for clarity

Ideal Skills and Experience:
- Proficiency in Python
- Strong understanding of memory management concepts
- Experience with FIFO page replacement algorithm
- Ability to write clear, detailed documentation