Problem: Given 2 integers u and v, find the shortest array such that [bitwise-xor](https://en.wikipedia.org/wiki/Bitwise_operation#XOR) of its elements is u, and the sum of its elements is v.

Input

The only line contains 2 integers u and v (0 ≤ u,v ≤ 10^{18}).

Output

If there's no array that satisfies the condition, print "-1". Otherwise:

The first line should contain one integer, n, representing the length of the desired array. The next line should contain n positive integers, the array itself. If there are multiple possible answers, print any.

Examples

Input


2 4


Output


2
3 1

Input


1 3


Output


3
1 1 1

Input


8 5


Output


-1

Input


0 0


Output


0

Note

In the first sample, 3⊕ 1 = 2 and 3 + 1 = 4. There is no valid array of smaller length.

Notice that in the fourth sample the array is empty.

Solution (in PYTHON3):

Solution:
def solve(u, v):
    if u == v:
        return [u]
    elif u > v:
        return None

    if (v - u) % 2 == 0:
        x = (v - u) // 2
        if u & x == 0:
            return [u | x, x]
        else:
            return [u, x, x]
    else:
        return None


# assert solve(2, 4) == [3, 1]
# assert solve(1, 3) == [1, 1, 1]
# assert solve(8, 5) is None
# assert solve(0, 0) == [0]

u, v = map(int, input().split())
r = solve(u, v)
if not r:
    print(-1)
elif u == v == 0:
    print(0)
else:
    print('{}\n{}'.format(len(r), ' '.join(map(str, r))))