# Learn How to Work with Numbers and Strings by Implementing the Luhn Algorithm - Step 35

### Tell us what’s happening:

I have changed the value of card_number variable,But It shows that my code is wrong.

``````
# User Editable Region

def verify_card_number(card_number):
sum_of_odd_digits = 0
card_number_reversed = card_number[::-1]
odd_digits = card_number_reversed[::2]

for digit in odd_digits:
sum_of_odd_digits += int(digit)

sum_of_even_digits = 0
even_digits = card_number_reversed[1::2]
for digit in even_digits:
number = int(digit) * 2
if number >= 10:
number = (number // 10) + (number % 10)
sum_of_even_digits += number
total = sum_of_odd_digits + sum_of_even_digits

def main():
card_number = '4111-1111-4555-1141'
card_translation = str.maketrans({'-': '', ' ': ''})
translated_card_number = card_number.translate(card_translation)
verify_card_number(translated_card_number)
print(card_number)

main()

# User Editable Region

``````

User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36`

### Challenge Information:

Learn How to Work with Numbers and Strings by Implementing the Luhn Algorithm - Step 35

You need to change the `card_number` variable.

change the `card_number` back to something valid

``````    card_number = '4111-1111-4555-1141'
``````

Hang on. I don’t think that’s the actual issue. You see it appears that they deleted the “INVALID!” and “VALID!” output from the seeded code.

These four lines are needed to proceed.

``````    if verify_card_number(translated_card_number):
print('VALID!')
else:
print('INVALID!')
``````

Without them, our challenge has no way of knowing if they actually updated the `card_number` variable to be something valid.

1 Like

remove the `print` call from the `verify_card_number`

You removed the print calls from `main` instead.

Try to reset the step and double check the instructions