Question: what is cost of first class mail stamp
[{'answer': '. 49', 'provenance': [{'wikipedia_id': '1653050', 'title': 'History of United States postage rates', 'start_paragraph_id': 20, 'start_character': 160, 'end_paragraph_id': 20, 'end_character': 163, 'bleu_score': 1.0, 'section': 'Section::::Historical notes.\n'}]}, {'answer': '49 cents', 'provenance': [{'wikipedia_id': '1653050', 'title': 'History of United States postage rates', 'start_paragraph_id': 20, 'start_character': 161, 'end_paragraph_id': 20, 'end_character': 169, 'bleu_score': 1.0, 'section': 'Section::::Historical notes.\n'}]}, {'answer': '47 cents', 'provenance': [{'wikipedia_id': '1653050', 'title': 'History of United States postage rates', 'start_paragraph_id': 21, 'start_character': 369, 'end_paragraph_id': 21, 'end_character': 377, 'bleu_score': 1.0, 'section': 'Section::::Historical notes.\n'}]}, {'provenance': [{'wikipedia_id': '1653050', 'title': 'History of United States postage rates', 'start_paragraph_id': 20, 'start_character': 0, 'end_paragraph_id': 20, 'end_character': 343, 'bleu_score': 0.9684940092844061, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8344745003250079078}, 'section': 'Section::::Historical notes.\n'}]}, {'provenance': [{'wikipedia_id': '1653050', 'title': 'History of United States postage rates', 'start_paragraph_id': 21, 'start_character': 0, 'end_paragraph_id': 21, 'end_character': 490, 'bleu_score': 0.9776501033621461, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8344745003250079078}, 'section': 'Section::::Historical notes.\n'}]}, {'provenance': [{'wikipedia_id': '1653050', 'title': 'History of United States postage rates', 'section': 'Section::::Historical notes.\n', 'start_paragraph_id': 20, 'end_paragraph_id': 20, 'meta': {'evidence_span': ['On September 25, 2013, the USPS announced a 3 cent increase in the First Class postal rate, to be effective January 26, 2014, increasing the price of a stamp to 49 cents. Bulk mail, periodicals, and package service rates were also increased by 6 percent. A loss of US$5 billion during the 2013 fiscal year was the reason given for the increase', 'Bulk mail, periodicals, and package service rates were also increased by 6 percent. A loss of US$5 billion during the 2013 fiscal year was the reason given for the increase.', 'On September 25, 2013, the USPS announced a 3 cent increase in the First Class postal rate, to be effective January 26, 2014, increasing the price of a stamp to 49 cents.']}}]}]