Question: how many times have forest won the european cup
[{'answer': '2', 'provenance': [{'wikipedia_id': '157294', 'title': 'Nottingham Forest F.C.', 'start_paragraph_id': 2, 'start_character': 244, 'end_paragraph_id': 2, 'end_character': 245, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]