Which main character dies at the end of the movie the Avengers Endgame?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q23894967', 'id': 0, 'label': 'Tony Stark'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q23781155', 'id': 1, 'label': 'Avengers: Endgame'}], 'links': [{'name_': 'P674', 'source': 1, 'target': 0, 'label': 'characters'}]}