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:
# cook your dish here
u,v = map(int,input().split())
if u > v:
    print(-1)
    
elif u == v and u == 0:
    print(0)

elif u == v:
    print(1)
    print(u)
    
elif (u%2==0 and v%2 != 0) or (u%2!=0 and v%2 == 0):
    print(-1)
    
elif u == 1:
    print(v)
    for i in range(v):
        print(1,end=' ')
    print()
    
else:
    a = (v-u)//2
    b = (v-u)//2+u
    if a^b == u:
        print(2)
        print(a,b)
    else:
        print(3)
        print(u,a,a)