#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); ++i)

int main() {
  ll n, s;
  cin >> n >> s;
  vector<int> ans(0);
  for (int i = n; i > 0; i--) {
    if (s >= i) {
      ans.push_back(i);
      s -= i;
    }
  }
  assert(s == 0);
  sort(ans.begin(), ans.end());
  cout << ans.size() << endl;
  for (auto x : ans) cout << x << " ";
  cout << endl;
  return 0;
}