def remove_noise(ftm_df):
    """
    Remove noise of the original FTM dataset.

    Parameters
    ----------
    ftm_df : pandas.DataFrame
        original FTM dataset.

    Returns
    -------
    pandas.DataFrame
        pandas.DataFrame with two columns, title and abstract with removed
        noise.

    """
    ftm_df = ftm_df.dropna()
    ftm_df = ftm_df.rename(columns={"file_name_sort": "title", "content": "abstract"})
    remove = ['.DS_Store', 'NaN', 'Readme.md']

    return ftm_df[~ftm_df.title.isin(remove)]