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 CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 20;
const double eps = 1e-5;
int dir[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
using namespace std;
int main() {
  long long u, v;
  cin >> u >> v;
  if (!u && !v) {
    cout << 0 << endl;
    return 0;
  }
  if (v < u || (u + v) % 2) {
    cout << -1 << endl;
    return 0;
  } else if (u == v) {
    cout << 1 << endl;
    cout << u << endl;
    return 0;
  } else {
    long long t1 = (v + u) / 2;
    long long t2 = (v - u) / 2;
    if ((t1 ^ t2) == u && t1 + t2 == v) {
      cout << 2 << endl;
      cout << t1 << " " << t2 << endl;
      return 0;
    }
    cout << 3 << endl;
    cout << u << " " << (v - u) / 2 << " " << (v - u) / 2 << endl;
  }
}