Can you repair this program?

Question

This is a program I wrote test to learn from experience. But it has an error that I cannot understand
Can you explain this error and how to fix it (Error code I will note in the program in the location where the error is encountered)
Thank you
Link: https://code.sololearn.com/cA16a05A10A1

Answer 1

🔹Try to add global x in decode function
______________
def decode():
global x
# codes
...
______________

🔹Another way is to pass an argument to function.
______________
def decode(x):
# some codes
...

...
# call function with argument.
if y == 0:
decode(x)
______________

Please update us if this is still wrong. Thanks.
https://code.sololearn.com/cdpGe0WwIyAz/?ref=app

Answer 2

Value is not assigned to x.