Question: who sang theme song for greatest american hero
[{'answer': 'American singer Joey Scarbury', 'provenance': [{'wikipedia_id': '30200514', 'title': 'Theme from The Greatest American Hero (Believe It or Not)', 'start_paragraph_id': 1, 'start_character': 136, 'end_paragraph_id': 1, 'end_character': 165, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '30200514', 'title': 'Theme from The Greatest American Hero (Believe It or Not)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 341, 'bleu_score': 0.9663744727315161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3786838107291669629}, 'section': 'Section::::Abstract.'}]}]