A, B = map(int, input().split())
binA = format(A, 'b')
binB = format(B, 'b')

if len(binA)<=len(binB):
    binA = '0'*(len(binB)-len(binA))+binA
else:
    binB = '0'*(len(binA)-len(binB))+binB

c1, c2, c3, c4 = 0, 0, 0, 0

for binA_i, binB_i in zip(binA, binB):
    if binA_i=='1' and binB_i=='1':
        c1 += 1
    elif binA_i=='1' and binB_i=='0':
        c2 += 1
    elif binA_i=='0' and binB_i=='1':
        c3 += 1
    elif binA_i=='0' and binB_i=='0':
        c4 += 1

if c2>0:
    print(0)
elif c3==0:
    print(1)
else:
    print(2**(c3-1))