#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int xor_, sum;
  cin >> xor_ >> sum;
  long long int diff = sum - xor_;
  if (diff == 0) {
    if (sum == 0) {
      cout << 0 << endl;
      return 0;
    }
    cout << 1 << endl;
    cout << sum << endl;
    return 0;
  }
  if (diff % 2 != 0 || diff < 0) {
    cout << "-1" << endl;
    return 0;
  }
  long long int and_ = diff / 2;
  bool res = true;
  long long int a = 0, b = 0;
  for (int i = 0; i < 63 && res; i++) {
    long long int and_bit = ((and_ >> i) & 1ll);
    long long int xor_bit = ((xor_ >> i) & 1ll);
    if ((xor_bit == 1 && and_bit == 1)) {
      res = false;
      a = 0;
      b = 0;
    } else if (xor_bit == 1 && and_bit == 0) {
      a = a | (1ll << i);
    } else if (xor_bit == 0 && and_bit == 1) {
      a = a | (1ll << i);
      b = b | (1ll << i);
    }
  }
  if (res) {
    cout << "2" << endl;
    cout << a << " " << b << endl;
    return 0;
  }
  a = xor_;
  b = diff / 2;
  long long int c = diff / 2;
  cout << "3" << endl;
  cout << a << " " << b << " " << c << endl;
  return 0;
}
