Problem in the space in the output

Question

A little problem in the space any one to help me plz 😕😕💔
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from string import*
h=ascii_lowercase
H=ascii_uppercase
B=''
j=h[::-1]
R=input()
for i in R:
if i=='':
B+=i
elif i in h :
L=h.find(i)
B+=j[L]
elif i in H :
L=H.find(i)
B+=j[L]
print (B)
This is the code

Answer 1

missed the space between quotes
if i == " "

Answer 2

It's a prgm that takes a message as input and replaces esch letter by the corresponding letter in the backwards of the alphabet for exp a by z or b by y.. And the little problem that when the prgrm is running it ignores the spaces