def is_even(n):
    '''
    Return True if n is even and False if n is odd.

    >>> is_even(0)
    True
    >>> is_even(7)
    False
    >>> is_even(-8)
    True
    '''
    return n % 2 == 0


def absolute_value(n):
    if n < 0:
        return -n
    else:
        return n


def factorial(n):
    result = 1
    for i in range(1, n + 1):
        result = result * i
    return result


players = ['Ada', 'Teal', 'Sam', 'Jo']
scores = {'Ada': 10, 'Teal': 13}
print('players:', len(players))
print('everyone can pair up:', is_even(len(players)))
print('score gap:', absolute_value(scores['Ada'] - scores['Teal']))
print('possible playing orders:', factorial(len(players)))