Question: how many unlockable characters in super smash bros
[{'answer': 'four', 'provenance': [{'wikipedia_id': '1577869', 'title': 'Super Smash Bros.', 'start_paragraph_id': 1, 'start_character': 489, 'end_paragraph_id': 1, 'end_character': 493, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1577869', 'title': 'Super Smash Bros.', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 395, 'bleu_score': 0.9684940092844061, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8216640245098117124}, 'section': 'Section::::Games.:"Super Smash Bros." (1999).\n'}]}]