import typing


def days(day: typing.Union[str, int]) -> str:
    """
    Humanize the number of days.

    Parameters
    ----------
    day: Union[int, str]
        The number of days passed.

    Returns
    -------
    str
        A formatted string of the number of days passed.
    """
    day = int(day)
    if day == 0:
        return '**today**'
    return f'{day} day ago' if day == 1 else f'{day} days ago'