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:
from sys import stdin, stdout
import math,sys
#sys.stdin=open('input.txt','r')
#sys.stdout=open('output.txt','w')
from itertools import permutations, combinations
from collections import defaultdict
import bisect
import heapq as hq



def main():
    try:
        u,v=map(int,input().split())
        if u==0 and v==0:
            print(0)
            exit()
        if u%2!=v%2 or u>v:
            print(-1)
            exit(0)
        if u==v:
            print(1)
            print(v)
            exit()
        x=(v-u)//2
        y=x^u
        if x+y==v:
            print(2)
            print(x,y)
            
        else:
            print(3)
            print(u,x,x)


        
    except:
        pass 

    

M=998244353
P = 1000000007
if __name__ == '__main__':
    main()