import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	A, B = getlist()
	val = 0
	jud = 1
	for i in range(35):
		if A % 2 == 1 and B % 2 == 0:
			jud = 0
			break

		elif A % 2 == 0 and B % 2 == 1:
			val += 1

		A >>= 1; B >>= 1

	if jud == 0:
		print(0)
	else:
		if val == 0:
			print(1)
		else:
			ans = 2 ** (val - 1)
			print(ans)
		




if __name__ == '__main__':
	main()