def get_fix_string(input_string: str, length: int):
    """
    Transforms input_string to the string of the size length.

    Parameters
    ----------
    input_string : str
        input_string
    length : int
        length of output_string, if -1 then output_string is the same as input_string

    Returns
    -------
    str
        beautiful string of the size length

    """
    input_string = str(input_string)
    if length < 0:
        output_string = input_string
    elif len(input_string) > length:
        sep = (length - 3) // 2
        if length % 2 == 0:
            output_string = input_string[:sep + 1] + '...' + input_string[-sep:
                ]
        else:
            output_string = input_string[:sep] + '...' + input_string[-sep:]
    else:
        output_string = input_string + ' ' * (length - len(input_string))
    return output_string
