#include <bits/stdc++.h>
using namespace std;
struct Value {
  long long int input;
  long long int output;
};
long long int findOutput(long long int n) {
  long long int k = 0;
  while (n) {
    if (n & 1) return pow(2, k);
    k++;
    n >>= 1;
  }
  return 0;
}
void Solve() {
  long long int sum, limit;
  cin >> sum >> limit;
  Value value[limit];
  for (long long int i = 1; i <= limit; i++) {
    value[i - 1].input = i;
    value[i - 1].output = findOutput(i);
  }
  sort(value, value + limit,
       [](Value a, Value b) { return a.output > b.output; });
  vector<long long int> ans;
  for (long long int i = 1; i <= limit; i++) {
    if (sum >= value[i - 1].output) {
      ans.push_back(value[i - 1].input);
      sum -= value[i - 1].output;
    }
  }
  if (sum)
    cout << -1;
  else {
    cout << ans.size() << endl;
    for (long long int i = 0; i <= ans.size() - 1; i++) cout << ans[i] << " ";
  }
  cout << endl;
}
int main(int argc, char const *argv[]) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(0);
  ;
  int T = 1;
  while (T--) Solve();
  return 0;
}
