# Learn Recursion by Solving the Tower of Hanoi Puzzle - Step 40

### Tell us what’s happening:

I honestly have no clue what is going on here, I’m so confused. None of this makes any sense.

``````NUMBER_OF_DISKS = 4
number_of_moves = 2**NUMBER_OF_DISKS - 1
rods = {
'A': list(range(NUMBER_OF_DISKS, 0, -1)),
'B': [],
'C': []
}

def make_allowed_move(rod1, rod2):
forward = False
if not rods[rod2]:
forward = True
elif rods[rod1] and rods[rod1][-1] < rods[rod2][-1]:
forward = True

if forward:
print(f'Moving disk {rods[rod1][-1]} from {rod1} to {rod2}')
rods[rod2].append(rods[rod1].pop())
else:
print(f'Moving disk {rods[rod2][-1]} from {rod2} to {rod1}')
rods[rod1].append(rods[rod2].pop())

# display our progress
print(rods, '\n')

def move(n, source, auxiliary, target):
# display starting configuration
print(rods, '\n')
for i in range(number_of_moves):
remainder = (i + 1) % 3
if remainder == 1:
if n % 2 != 0:
print(f'Move {i + 1} allowed between {source} and {target}')
make_allowed_move(source, target)

# User Editable Region

else:
print(f'Move {i + 1} allowed between {source} and {auxiliary}')
make_allowed_move(source, auxiliary)

elif remainder == 2:
print(f'Move {i + 1} allowed between {source} and {auxiliary}')

if (i + 1) % 2 != 0:
make_allowed_move(source, auxiliary)

elif remainder == 0:
print(f'Move {i + 1} allowed between {auxiliary} and {target}')
make_allowed_move(auxiliary, target)

# User Editable Region

elif remainder == 0:
print(f'Move {i + 1} allowed between {auxiliary} and {target}')
make_allowed_move(auxiliary, target)

# initiate call from source A to target C with auxiliary B
move(NUMBER_OF_DISKS, 'A', 'B', 'C')
``````

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### Challenge Information:

Learn Recursion by Solving the Tower of Hanoi Puzzle - Step 40

It sounds like you are doing something similar to an earlier step.

Do you have a more specific question? Try to focus on the current instruction:

Now you need to do the same with your `elif` statement: put the `print()` and `make_allowed_move()` calls inside an `if` statement to execute when `n` is odd.

Is there a confusing part or do you have a question about something?

Is it the overall context? Do you want to see an example of Tower of Hanoi? Maybe it would help to see how it works.
https://www.mathsisfun.com/games/towerofhanoi.html

Without a more specific question it’s really difficult to help here.

Try starting with this part:

put the `print()` and `make_allowed_move()` calls inside an `if` statement

Then focus on the condition:

execute when `n` is odd.

How do you execute when n is odd?

How can you tell if a number is even or odd?

(You did this already in Step 38)

my code:

``````    elif remainder == 2:
if n % 2 != 0:
print(f'Move {i + 1} allowed between {source} and {auxiliary}')
# make_allowed_move(source, auxiliary)
``````

prompte：