def automatic_nch(f_min, f_max, spacing):
    """How many channels are available in the spectrum

    :param f_min Lowest frequenecy [Hz]
    :param f_max Highest frequency [Hz]
    :param spacing Channel width [Hz]
    :return Number of uniform channels

    >>> automatic_nch(191.325e12, 196.125e12, 50e9)
    96
    >>> automatic_nch(193.475e12, 193.525e12, 50e9)
    1
    """
    return int((f_max - f_min) // spacing)