import re


def last_name_first_author(authors):
    """Return displays of info based on the authors field

    Selects the last name of the first author

    Doctest:

    .. doctest::
        >>> last_name_first_author('Pimentel, Joao')
        'pimentel'
        >>> last_name_first_author('Pimentel, Joao and Braganholo, Vanessa')
        'pimentel'
        >>> last_name_first_author('Joao Pimentel')
        'pimentel'
        >>> last_name_first_author('Joao Pimentel and Vanessa Braganholo')
        'pimentel'
        >>> last_name_first_author('Joao Pimentel, Vanessa Braganholo')
        'pimentel'
    """
    if " and " in authors:
        authors = authors.split(" and ")[0]
    if "," not in authors:
        last = authors.split()[-1]
    else:
        last = re.findall(r'(\w*)[`\-=~!@#$%^&*()_+\[\]{};\'\\:"|<,/<>?]', authors)[0]
    return last.lower()