critics = {'Lisa Rose': {'Lady in the Water': 2.5, 'Snakes on a Plane': 3.5,
                         'Just My Luck': 3.0, 'Superman Returns': 3.5, 'You, Me and Dupree': 2.5,
                         'The Night Listener': 3.0},
           'Gene Seymour': {'Lady in the Water': 3.0, 'Snakes on a Plane': 3.5,
                            'Just My Luck': 1.5, 'Superman Returns': 5.0, 'The Night Listener': 3.0,
                            'You, Me and Dupree': 3.5},
           'Michael Phillips': {'Lady in the Water': 2.5, 'Snakes on a Plane': 3.0,
                                'Superman Returns': 3.5, 'The Night Listener': 4.0},
           'Claudia Puig': {'Snakes on a Plane': 3.5, 'Just My Luck': 3.0,
                            'The Night Listener': 4.5, 'Superman Returns': 4.0,
                            'You, Me and Dupree': 2.5},
           'Mick LaSalle': {'Lady in the Water': 3.0, 'Snakes on a Plane': 4.0,
                            'Just My Luck': 2.0, 'Superman Returns': 3.0, 'The Night Listener': 3.0,
                            'You, Me and Dupree': 2.0},
           'Toby': {'Snakes on a Plane': 4.5, 'You, Me and Dupree': 1.0, 'Superman Returns': 4.0},
           'Jack Matthews': {'Lady in the Water': 3.0, 'Snakes on a Plane': 4.0,
                             'The Night Listener': 3.0, 'Superman Returns': 5.0, 'You, Me and Dupree': 3.5},
           'Chang': {'Lady in the Water': 1.0, 'Snakes on a Plane': 1.5,
                    'The Night Listener': 1.0, 'Superman Returns': 4.0, 'You, Me and Dupree': 1.5}}

def get_all_movie_names():
    movie_names = []
    for movie_scores in critics.values():
        for movie_name in movie_scores:
            if movie_name not in movie_names:
                movie_names.append(movie_name)

    return movie_names
