Question: when was the first episode of the challenge
[{'answer': 'on June 1 , 1998', 'provenance': [{'wikipedia_id': '1475688', 'title': 'The Challenge (TV series)', 'start_paragraph_id': 2, 'start_character': 21, 'end_paragraph_id': 2, 'end_character': 37, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]