Who was the vice president of Abraham Lincoln and also the first US president to be impeached?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'INTERNAL', 'name_': 'Q19180675', 'id': 0, 'label': 'Small Brockhaus and Efron Encyclopedic Dictionary'}, {'type': 'INTERNAL', 'name_': 'Q30', 'id': 1, 'label': 'United States of America'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q11696', 'id': 2, 'label': 'President of the United States'}, {'type': 'INTERNAL', 'name_': 'Q2657718', 'id': 3, 'label': 'Armenian Soviet Encyclopedia'}, {'type': 'INTERNAL', 'name_': 'Q5292', 'id': 4, 'label': 'encyclopedia'}, {'type': 'INTERNAL', 'name_': 'Q19652', 'id': 5, 'label': 'public domain'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q19047539', 'id': 6, 'label': "Collier's New Encyclopedia, 1921"}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q91', 'id': 7, 'label': 'Abraham Lincoln'}, {'type': 'INTERNAL', 'name_': 'Q29364', 'id': 8, 'label': 'Montgomery'}, {'type': 'INTERNAL', 'name_': 'Q20504925', 'id': 9, 'label': 'John Adams'}], 'links': [{'name_': 'P6216', 'source': 0, 'target': 5, 'label': 'copyright status'}, {'name_': 'P1343', 'source': 1, 'target': 0, 'label': 'described by source'}, {'name_': 'P17', 'source': 1, 'target': 1, 'label': 'country'}, {'name_': 'P1906', 'source': 1, 'target': 2, 'label': 'office held by head of state'}, {'name_': 'P1343', 'source': 1, 'target': 3, 'label': 'described by source'}, {'name_': 'P6', 'source': 1, 'target': 7, 'label': 'head of government'}, {'name_': 'P136', 'source': 3, 'target': 4, 'label': 'genre'}, {'name_': 'P31', 'source': 6, 'target': 4, 'label': 'instance of'}, {'name_': 'P6216', 'source': 6, 'target': 5, 'label': 'copyright status'}, {'name_': 'P1343', 'source': 7, 'target': 0, 'label': 'described by source'}, {'name_': 'P27', 'source': 7, 'target': 1, 'label': 'country of citizenship'}, {'name_': 'P39', 'source': 7, 'target': 2, 'label': 'position held'}, {'name_': 'P1343', 'source': 7, 'target': 3, 'label': 'described by source'}, {'name_': 'P1343', 'source': 8, 'target': 0, 'label': 'described by source'}, {'name_': 'P17', 'source': 8, 'target': 1, 'label': 'country'}, {'name_': 'P1343', 'source': 8, 'target': 6, 'label': 'described by source'}, {'name_': 'P495', 'source': 9, 'target': 1, 'label': 'country of origin'}, {'name_': 'P180', 'source': 9, 'target': 2, 'label': 'depicts'}, {'name_': 'P6216', 'source': 9, 'target': 5, 'label': 'copyright status'}]}