def parse_page_range(page_range):
    pages = set()

    for part in page_range.split(","):
        part = part.strip()

        if "-" in part:
            start, end = map(int, part.split("-"))
            pages.update(range(start, end + 1))
        else:
            pages.add(int(part))

    return sorted(pages)


examples = [
    "1-3",
    "1,3,5",
    "1-3,7,9-11",
    "2,4-6,10"
]

for example in examples:
    print(f"{example} -> {parse_page_range(example)}")