user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: What theme song is written by the person who plays a character called Dr. Roskin? 
Knowledge Triplets: Alan Thicke, music.composition.composer, The Facts of Life
Facts of Life, music.recording.song, Facts of Life
Alan Thicke, music.composition.composer, Hockey Sock Rock
Alan Thicke, music.composer.compositions, Hockey Sock Rock
Al Burton, music.composer.compositions, Facts of Life
Al Burton, music.composer.compositions, The Facts of Life
Dr. Roskin, film.film_character.portrayed_in_films, m.04dgp7n
Topic, freebase.type_profile.published, Published
Fictional Character, freebase.type_profile.kind, Portrayal
Film, type.domain.types, Film character
m.04dgp7n, film.performance.character, Dr. Roskin
Film character, common.topic.article, m.02_96_z
It Takes Diff'rent Strokes, tv.tv_theme_song.theme_song_for, Diff'rent Strokes
John LaSalle, music.composer.compositions, It Takes Diff'rent Strokes
It Takes Diff'rent Strokes, music.composition.composer, Al Burton
Facts of Life, music.composition.recordings, Facts of Life
Arnold & Willy (Diff'rent Strokes), music.composition.composer, Alan Thicke
m.0zxdsq6, dataworld.gardening_hint.replaced_by, The Facts of Life
Gloria Loring, music.composer.compositions, The Facts of Life
Facts of Life, music.composition.composer, Gloria Loring
It Takes Diff'rent Strokes, music.recording.song, It Takes Diff'rent Strokes
Gloria Loring, music.composer.compositions, Facts of Life
Facts of Life, music.composition.composer, Alan Thicke
It Takes Diff'rent Strokes, music.composition.recordings, Diff'rent Strokes Theme (live in DC)
Arnold & Willy (Diff'rent Strokes), music.composition.composer, Al Burton
Arnold & Willy (Diff'rent Strokes), music.composition.composer, Gloria Loring
m.04dgp7n, film.performance.actor, Alan Thicke
Alan Thicke, music.composer.compositions, Arnold & Willy (Diff'rent Strokes)
It Takes Diff'rent Strokes, music.composition.composer, John LaSalle
Diff'rent Strokes, tv.tv_program.theme_song, It Takes Diff'rent Strokes
Topic, freebase.type_profile.kind, Portrayal
Fictional Character, freebase.type_profile.published, Published
Alan Thicke, music.composer.compositions, Arnold & Willy (Diff'rent Strokes)
Film character, freebase.type_profile.strict_included_types, Topic
Dr. Roskin, common.topic.notable_for, g.125f5fm4y
Gloria Loring, music.composer.compositions, It Takes Diff'rent Strokes
Facts of Life, music.composition.composer, Al Burton
The Facts of Life, music.composition.composer, Al Burton
Diff'rent Strokes, music.recording.song, It Takes Diff'rent Strokes
Character, owl#inverseOf, Portrayed in films
Fictional Character, freebase.type_hints.included_types, Topic
Big Wheels, tv.tv_theme_song.theme_song_for, Wheel of Fortune
It Takes Diff'rent Strokes, music.composition.recordings, Diff'rent Strokes
Diff'rent Strokes (It Takes Diff'rent Strokes), music.recording.song, It Takes Diff'rent Strokes
Film character, type.type.expected_by, Other conquests
Film character, freebase.type_hints.included_types, Topic
Film character, freebase.type_profile.strict_included_types, Fictional Character
Film character, type.type.domain, Film
Alan Thicke, music.composer.compositions, Big Wheels
Tom Smith, music.composer.compositions, It Takes Diff'rent Strokes
Film character, freebase.type_profile.kind, Portrayal
Alan Thicke, film.actor.film, m.04dgp7n
Film character, freebase.type_hints.included_types, Fictional Character
Dr. Roskin, film.film_character.portrayed_in_films, m.04dgp7n
Arnold & Willy (Diff'rent Strokes), music.composition.recordings, Arnold & Willy (Diff'rent Strokes)
Hockey Sock Rock, music.composition.composer, Alan Thicke
Al Burton, music.composer.compositions, It Takes Diff'rent Strokes
Gloria Loring, music.composer.compositions, Arnold & Willy (Diff'rent Strokes)
Film character, freebase.type_profile.kind, Annotation
Character, type.property.reverse_property, Portrayed in films
Film character, type.type.properties, Portrayed in films
The Facts of Life, music.recording.song, Facts of Life
Alan Thicke, music.composer.compositions, The Facts of Life
Character, type.property.expected_type, Film character
Alan Thicke, music.composition.composer, Facts of Life
The Facts of Life, music.recording.song, The Facts of Life
Alan Thicke, music.composer.compositions, It Takes Diff'rent Strokes
It Takes Diff'rent Strokes, music.composition.composer, Gloria Loring
It Takes Diff'rent Strokes, music.composition.recordings, It Takes Diff'rent Strokes
It Takes Diff'rent Strokes, music.composition.composer, Tom Smith
Big Wheels, music.composition.composer, Alan Thicke
RoboDoc, film.film.starring, m.04dgp7n
It Takes Diff'rent Strokes, music.composition.recordings, Diff'rent Strokes (It Takes Diff'rent Strokes)
m.04dgp7n, film.actor.film, Alan Thicke
The Facts of Life, music.composition.recordings, The Facts of Life
Alan Thicke, music.composer.compositions, Facts of Life
Diff'rent Strokes Theme (live in DC), music.recording.song, It Takes Diff'rent Strokes
Fictional Character, freebase.type_profile.strict_included_types, Topic
Alan Thicke, music.composition.composer, Big Wheels
Film character, type.type.expected_by, Killed by
Film character, freebase.type_profile.published, Published
Alan Thicke, music.composition.composer, It Takes Diff'rent Strokes
Wheel of Fortune, tv.tv_program.theme_song, Big Wheels
Film character, type.type.properties, Portrayed in films (dubbed)
Al Burton, music.composer.compositions, Arnold & Willy (Diff'rent Strokes)
The Facts of Life, music.composition.composer, Alan Thicke
Character, rdf-schema#range, Film character
Film character, type.type.expected_by, Character
Arnold & Willy (Diff'rent Strokes), music.recording.song, Arnold & Willy (Diff'rent Strokes)
The Facts of Life, music.composition.composer, Gloria Loring
Facts of Life, music.composition.recordings, The Facts of Life
m.04dgp7n, film.performance.film, RoboDoc
Film character, type.type.expected_by, Character using Wham-O product
Dr. Roskin, common.topic.notable_types, Film character
It Takes Diff'rent Strokes, music.composition.composer, Alan Thicke

Answer: Facts of Life
The Facts of Life
Hockey Sock Rock
It Takes Diff'rent Strokes
Arnold & Willy (Diff'rent Strokes)
Big Wheels