Programa que pida por pantalla un número y diga si es par o impar.

regex that: match all words that start with "hello" and end with "world"
    and are not in the list of words that start with "hello" and end with "world"
    """
    regex = r"\bhello(?!\w*world\b)\w*\b"
    return re.compile(regex, re.IGNORECASE)

def