def cas2sas_timestamp(cdt):
    """
    Convert a CAS timestamp to a SAS timestamp

    Parameters
    ----------
    cdt : int
        CAS timestamp.

    Examples
    --------
    >>> cas2sas_timestamp(43200000000)
    43200.0

    Returns
    -------
    float
        SAS timestamp

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