Rating: 2.0

```
import base64

while True:
try:
with open("z", 'r+') as f:
string = f.read()[::-1]
text_decode = base64.b64decode(string).decode("utf-8")
f.seek(0)
f.write(text_decode)
f.truncate()
except UnicodeDecodeError and base64.binascii.Error:
flag = open("z", 'r+')
print(flag.read())
break
```

`AFFCTF{s1mPle_Rev4s_D0Ne_oNe1}`