Secret Code Python (Help pls)

Question

The problem I have is that I do not know how to make a COMPARISON of the letters of the alphabet with the letters that I enter from the word on the keyboard.
I know I can do it by other methods, but I want to try this one that I propose here, if in that case you wish. Please can you see my code posted on my profile. Thanks a lot.

#I have my code. I try to explain all in comments.
#
# Incomplete code
#Secret code: The objective is to write a word and that the first letter is replaced with the last letter, and so correspondingly,
# -> the second with the penultimate letter.
# -> the third with the third to last letter ...

cont_asc= -1
cont_des= 0

from string import ascii_lowercase
print ("The letters of the alphabet are: \n\t",ascii_lowercase)

#cap word, number of characters
def longitudCadena(w):
return len(w)
def nombrePropio(w):
return w.capitalize()
w=input('Input a word: ')
print(nombrePropio(w),'have',longitudCadena(w),'characters.')

#print ("String length is:", String length (w))
#change variable name
i=(longitudCadena(w))
#loop to see corresponding string space. The length is size taken and compared until it is other than 0 to exit the loop.
while i != 0:
i= i-1
print("'",w[i],"'","Corresponds to the cell ",i," of the chain")

#pulled apart
print("\nLetter correspondence:\n")

for x in (ascii_lowercase):
cont_asc= cont_asc +1
cont_des= cont_des -1
x = cont_asc
y = cont_des
#print (x,y)
print (
"First Letters: ",x,"->", ascii_lowercase[x],"\t",
"Last Letters: ",y,"->", ascii_lowercase[y])
#print (x, ascii_lowercase[x])
#print (y, ascii_lowercase[y])
#Counts in 25

Answer 1

it seems like a lot when you can just make a dictionary with each letter cooresponding to it's logical opposite.

alph_code = {'a': 'z', 'b': 'y', ...}

Answer 2

It's a good idea, because I'm doing it in the worst way jaja
Ty for that...