pages_list = set()
    last_num = None
    for p in range(len(pages)):
        if pages[p].isdigit():
            index = p + 1
            while index < len(pages) and pages[index].isdigit():
                index += 1
            if p - 1 < 0 or not pages[p - 1].isdigit():
                last_num = int(pages[p:index])
                pages_list.add(last_num)
            else:
                continue
        elif pages[p] == '-':
            for number in range(last_num, find_next_num(pages, p)):
                last_num = number
                pages_list.add(last_num)
        elif pages[p] == ',':
            continue
    final_list = list(pages_list)
    final_list.sort()
    return final_list


def find_next_num(pages, p):
    """Helper function."""
    last_num = None
    growing_index = p + 1
    while growing_index < len(pages) and pages[growing_index].isdigit():
        growing_index += 1
    if growing_index == p + 1:
        last_num = int(pages[p + 1])
    elif growing_index > p + 1:
        last_num = int(pages[p + 1:growing_index])
    return last_num