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
from math import gcd,sqrt,factorial,pi,inf
from collections import deque,defaultdict
from bisect import bisect,bisect_left
from time import time
from itertools import permutations as per
from heapq import heapify,heappush,heappushpop
input=stdin.readline
R=lambda:map(int,input().split())
I=lambda:int(input())
S=lambda:input().rstrip('\r\n')
L=lambda:list(R())
P=lambda x:stdout.write(str(x)+'\n')
lcm=lambda x,y:(x*y)//gcd(x,y)
nCr=lambda x,y:(f[x]*inv((f[y]*f[x-y])%N))%N
inv=lambda x:pow(x,N-2,N)
sm=lambda x:(x**2+x)//2
N=10**9+7

n,k=R()
if n>k or (k-n)&1:print(-1)
elif n==k==0:print(0)
else:
	if n==k:
		print(1)
		print(k)
	else:
		p=bin(n)[2:][::-1]
		q=bin((k-n)//2)[2:][::-1]
		m=0
		for i in range(min(len(p),len(q))):
			if p[i]==q[i]=='1':
				m=1
				break
		if m and n:
			print(3)
			print(n,(k-n)//2,(k-n)//2)
		else:
			print(2)
			print(n+(k-n)//2,(k-n)//2)