#include <bits/stdc++.h>
using namespace std;
void prexit() {
  printf("-1\n");
  exit(0);
}
int getBit(long long x, int pos) {
  if (x & (1LL << pos)) return 1;
  return 0;
}
int main() {
  long long u, v;
  scanf("%lld %lld", &u, &v);
  if (u > v || (v - u) % 2) prexit();
  if (u + v == 0) {
    printf("0\n");
    return 0;
  }
  if (u == v) {
    printf("1\n%lld\n", u);
    return 0;
  }
  int c = 0;
  long long a = 0, b = 0;
  bool flag = true;
  for (int i = 0; i < 62; i++) {
    if (getBit(u, i)) {
      b |= (1LL << i);
      if (getBit(v, i) != (c ^ 1)) {
        flag = false;
        break;
      }
    } else {
      if (getBit(v, i) != c) {
        flag = false;
        break;
      }
      if (getBit(u, i + 1) == getBit(v, i + 1))
        c = 0;
      else
        a |= (1LL << i), b |= (1LL << i), c = 1;
    }
  }
  if (flag) {
    printf("2\n%lld %lld\n", a, b);
    return 0;
  }
  printf("3\n%lld %lld %lld\n", u, (v - u) / 2, (v - u) / 2);
  return 0;
}
