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:
#! /usr/bin/env python
# -*- coding: utf-8 -*-
# vim:fenc=tf-8
#

"""
"""

from collections import defaultdict
from operator import itemgetter

import sys
input = sys.stdin.readline

def solve(u, v):
    vv = v - u
    if vv < 0 or vv%2==1:
        print(-1)
        return 1
    v2 = vv//2
    if u == 0 and v == 0:
        print(0)
    elif vv == 0:
        print(1)
        print(u)
    elif u|v2 == u+v2:
        print(2)
        print(u+v2,v2)
    else:
        print(3)
        print(u,v2,v2)



def main():
    u, v = map(int,input().split())
    solve(u, v)


if __name__ == "__main__":
    main()