def counting_number(number):
    """
    Creates a counting number string (e.g. "1st", "2nd", "3rd", "4th" ...) from
    an integer number.
    :param number: an integer number
    :returns: a string
    """
    s = str(number)
    if s.endswith('1') and not s.endswith('11'):
        return f'{s}st'
    elif s.endswith('2') and not s.endswith('12'):
        return f'{s}nd'
    elif s.endswith('3') and not s.endswith('13'):
        return f'{s}rd'
    else:
        return f'{s}th'
