完成python pta的编程作业：
n = int(input())
vertices = set()
edges = 0
total_length = 0for _ in range(n):line = input()vertex_dict = eval(line)vertex = list(vertex_dict.keys())[0]vertices.add(vertex)for neighbor, length in vertex_dict[vertex].items():vertices.add(neighbor)edges += 1total_length += lengthprint(len(vertices), edges, total_length)
input_str = input()
element_list = input_str.split()reversed_str = ''.join(reversed(element_list))
print(reversed_str)print(element_list)reversed_elements = ' '.join(reversed(element_list))
print(reversed_elements)
a_class = set(input())
b_class = set(input().split())
acm_racers = set(input().split())
english_racers = set(input().split())
transfer_student = input()all_students = a_class.union(b_class)
print(f"Total: {len(all_students)}")not_in_race = all_students - acm_racers - english_racers
print(f"Not in race: {sorted(not_in_race)}, num: {len(not_in_race)}")all_racers = acm_racers.union(english_racers)
print(f"All racers: {sorted(all_racers)}, num: {len(all_racers)}")both_racers = acm_racers.intersection(english_racers)
print(f"ACM + English: {sorted(both_racers)}, num: {len(both_racers)}")only_acm = acm_racers - english_racers
print(f"Only ACM: {sorted(only_acm)}")only_english = english_racers - acm_racers
print(f"Only English: {sorted(only_english)}")acm_or_english = only_acm.union(only_english)
print(f"ACM Or English: {sorted(acm_or_english)}")if transfer_student in a_class:a_class.remove(transfer_student)print(sorted(a_class))
elif transfer_student in b_class:b_class.remove(transfer_student)print(sorted(b_class))
