#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization("unroll-loops")
using namespace std;
const long long MOD = 1e+9 + 7;
const long long INF = 0x7f7f7f7f7f7f7f7f;
const int INFi = 0x7f7f7f7f;
const long long MAXN = 1e+5 + 7;
vector<long long> adj[MAXN];
long long visit[MAXN] = {};
int dx8[] = {0, 1, 1, 1, 0, -1, -1, -1}, dy8[] = {1, 1, 0, -1, -1, -1, 0, 1};
int dx4[] = {0, 1, 0, -1}, dy4[] = {1, 0, -1, 0};
int t = 1;
long long sum, limit;
vector<long long> ans;
long long lowbit(long long x) {
  long long count1 = -1;
  while (x > 0) {
    if (x % 2) {
      count1++;
      break;
    }
    count1++;
    x /= 2;
  }
  return count1;
}
void MAIN() {
  cin >> sum >> limit;
  for (long long i = limit; i >= 1; i--) {
    if (sum >= pow(2, lowbit(i))) {
      sum -= pow(2, lowbit(i));
      ans.push_back(i);
    }
    if (sum == 0) {
      cout << ans.size() << endl;
      for (auto it : ans) cout << it << " ";
      return;
    }
  }
  cout << -1;
  return;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cout << fixed;
  cout << setprecision(10);
  ;
  mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
  ;
  while (t--) {
    MAIN();
  }
}
