q = []


def length():
    """Returns number of waiting customers"""
    return len(q)


def show():
    """SHOW queue: print list of waiting customers.
    Customer waiting longest
    are shown at the end of the list."""
    print(q)
    q.reverse


def add(name):
    """Customer with name 'name' joining the queue"""
    q.insert(0, name)


def next_():
    """Returns name of next customer to serve, removes
    customer from queue"""
    next_customer = q.pop()
    return next_customer


add("Peter")
add("Mary")
add("Paul")