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:
# http://codeforces.com/problemset/problem/1325/D

import sys

u, v = [int(v) for v in sys.stdin.readline().split()]

def m():
    if (v-u) % 2 == 1:
        return None

    ar = []
    h = (v - u) // 2
    if u & h == 0:
        ar.append(u | h)
        ar.append(h)
    else:
        ar.append(u)
        ar.append(h)
        ar.append(h)
    return ar

if u > v:
    print(-1)
elif u == v:
    if u == 0:
        print(0)
    else:
        print(1)
        print(u)
else:
    ar = m()
    if ar is not None:
        print(len(ar))
        print(" ".join(map(str, ar)))
    else:
        print(-1)