# Mục đích là tìm dãy số thiếu trong dải number trong files numbers.txt
# file name: find_missing_numbers.py

def find_missing_numbers(filename, start=1, end=4384):
    # Read all numbers from file
    with open(filename, "r") as f:
        numbers = set()
        for line in f:
            line = line.strip()
            if line.isdigit():               # ensure it's a number
                numbers.add(int(line))

    # Generate full valid range
    full_range = set(range(start, end + 1))

    # Find what is missing
    missing = sorted(full_range - numbers)

    return missing


# Example usage:
missing_numbers = find_missing_numbers("numbers.txt")
print("Missing numbers:", missing_numbers)