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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def longest_monotonic_subseq_length(xs):
    '''Return the length of the longest monotonic subsequence of xs, second
    return value is the difference between increasing and decreasing lengths.

    >>> longest_monotonic_subseq_length((4, 5, 1, 2, 3))
    (3, 1)
    >>> longest_monotonic_subseq_length((1, 2, 3, 5, 4))
    (4, 2)
    >>> longest_monotonic_subseq_length((1, 2, 1))
    (2, 0)
    '''
    li = longest_increasing_subseq_length(xs)
    ld = longest_decreasing_subseq_length(xs)
    return max(li, ld), li - ld