Python 加密解密代码：简单字符偏移加密

import os

a = 0
flag = input()

for i in range(len(flag)):
    a += 1

if a != 32 or flag[0] != 'f' or flag[1] != 'l' or flag[2] != 'a' or flag[3] != 'g' or flag[4] != '{' or flag[31] != '}':
    print('error')
    exit()

tmp = []
for i in range(a):
    tmp.append(flag[i])

for i in range(a):
    tmp[i] = ord(tmp[i]) - 9

for i in range(a):
    print(chr(tmp[i]), end='')

注：该代码是一段简单的加密解密代码，将输入的字符串进行简单的减法操作后输出。