func main()
	var ss: [][]char :: cui@input().split(" ")
	var A: int :: ss[0].toInt(&)
	var B: int :: ss[1].toInt(&)
	var ans: int :: 0
	var cnt: int :: 0
	if(A = B)
		do cui@print("1\n")
		ret
	elif(A < B)
		while(B <> 0)
			if(B % 2 = 1)
				if(A % 2 = 0)
					do cnt :+ 1
				end if
			else
				if(A % 2 = 1)
					do cui@print("0\n")
					ret
				end if
			end if
			do A :/ 2
			do B :/ 2
		end while
	end if
	if(cnt <> 0)
		do ans :: 2 ^ (cnt - 1)
	end if
	do cui@print("\{ans}\n")
end func