def cas2sas_time(cdt):
    """
    Convert a CAS time to a SAS time

    Parameters
    ----------
    cdt : int
        CAS time.

    Examples
    --------
    >>> cas2sas_time(43200000000)
    43200.0

    Returns
    -------
    float
        SAS time

    """
    return cdt / float(10 ** 6)
