Python 3, how to get the contents in the innermost parentheses in the string with parentheses ()

>>> s = '(((x12 & x20) & x05) | x02) | ((x12 & x13)) | (x13 | x20)'
>>> Answer = ''
>>> Depth = 0
>>> Highest Depth = 0
>>> for c in s:
    if c == '(':
        Depth += 1
        Node string = ''
    elif c == ')':
        print('--'* depth, node string)
        If Depth > Maximum Depth:
            Maximum depth = depth
            Answer = Node string
        Depth - = 1
    else:
        Node string += c


------ ------ x12 & x20
---- ---- x12 & x20 & x05
-- -- x12 & x20 & x05 | x02
---- ---- x12 & x13
-- -- x12 & x13
-- -- x13 | x20
>>> Answer
'x12 & x20'
>>>