Question: how many republicans are up for reelection in the senate in 2018
[{'answer': '8', 'provenance': [{'wikipedia_id': '38680975', 'title': '2018 United States Senate elections', 'start_paragraph_id': 0, 'start_character': 3, 'end_paragraph_id': 0, 'end_character': 4, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]