def lscan; gets.split.map(&:to_i); end

a,b = lscan

if a == b
  p 1
  exit
end

x = a&(b^((1 << 32)-1))
if x != 0
  p 0
  exit
end
u = b&(a^((1 << 32)-1))
c = u.to_s(2).count('1')
p 1 << (c-1)

# (0..127).each do |x|
#   (x..128).each do |y|
#     if x&y == a && x|y == b
#       p [x, y]
#     end
#   end
# end