s, x = [int(i) for i in input().split()]
d = s - x
if d % 2:
print(0)
elif (d >> 1) & x:
print(0)
else:
count = 2**(bin(x).count('1'))
if d == 0:
count -= 2
print(count)237A - Free Cash | 1615B - And It's Non-Zero |
1619E - MEX and Increments | 34B - Sale |
1436A - Reorder | 1363C - Game On Leaves |
1373C - Pluses and Minuses | 1173B - Nauuo and Chess |
318B - Strings of Power | 1625A - Ancient Civilization |
864A - Fair Game | 1663B - Mike's Sequence |
448A - Rewards | 1622A - Construct a Rectangle |
1620A - Equal or Not Equal | 1517A - Sum of 2050 |
620A - Professor GukiZ's Robot | 1342A - Road To Zero |
1520A - Do Not Be Distracted | 352A - Jeff and Digits |
1327A - Sum of Odd Integers | 1276A - As Simple as One and Two |
812C - Sagheer and Nubian Market | 272A - Dima and Friends |
1352C - K-th Not Divisible by n | 545C - Woodcutters |
1528B - Kavi on Pairing Duty | 339B - Xenia and Ringroad |
189A - Cut Ribbon | 1182A - Filling Shapes |