方法1:

num = int(input())

thousand = (num // 1000 + 3 ) % 9

hundred = (num // 100 % 10 + 3 ) % 9

ten = (num // 10 % 10 + 3 ) % 9

one = (num % 10 + 3 ) % 9

print(str(ten) + str(one) + str(thousand) + str(hundred))

方法2:

num_str = input()

list_result = []

for _ in list(num_str):

result = (int(_) + 3) % 9

list_result.append(result)

print(str(list_result[2]) + str(list_result[3]) + str(list_result[0]) + str(list_result[1]))