#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
void printv(vector<long long> arr, long long n) {
  for (long long i = 0; i < n; ++i) cout << arr[i] << " ";
  cout << endl;
}
void print(long long arr[], long long n) {
  for (long long i = 0; i < n; ++i) cout << arr[i] << " ";
  cout << endl;
}
bool isPrime(long long n) {
  bool flag = 1;
  for (long long i = 2; i <= sqrt(n); ++i) {
    if (n % i == 0) {
      flag = 0;
      break;
    }
  }
  return (flag ? 1 : 0);
}
long long mod_power(long long x, long long y) {
  long long res = 1;
  while (y) {
    if (y & 1) res = (res * x) % MOD;
    x = (x * x) % MOD;
    y >>= 1;
  }
  return res;
}
void test_case() {
  long long n, k;
  cin >> n >> k;
  long long val = k, sum = 0;
  vector<long long> ans;
  while (val > 0) {
    long long S = __builtin_ctz(val);
    S = pow(2, S);
    --val;
    if (S + sum > n) continue;
    sum += S;
    ans.push_back(val + 1);
  }
  if (sum == n) {
    cout << ans.size() << '\n';
    printv(ans, ans.size());
  } else {
    cout << "-1\n";
  }
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  long long T = 1;
  while (T--) {
    test_case();
  }
  return 0;
}
