def _gaspr_input(endfin, pendfin, pendfout,
                 **kwargs):
    """
    Write gaspr input.

    Parameters
    ----------
    endfin : `int`
        tape number for input ENDF-6 file
    pendfin : `int`
        tape number for input PENDF file
    pendfout : `int`
        tape number for output PENDF file

    Returns
    -------
    `str`
        gaspr input text
    """
    text = ["gaspr"]
    text += [f"{endfin:d} {pendfin:d} {pendfout:d} /"]
    return "\n".join(text) + "\n"