where to write the final (else statement) in this python code?

i am new at learning python and i like to try things so i wrote this if and else statements in (python 3.4.3) shell but i don't know where to write the final else statement that leads to all 4 values are false.

this is a screenshot of the code because the code inserting feature here always cutting a big part of my code note that :

a=False
b=False
c=False
d=False