#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <deque>
#include <iomanip>
using namespace std;
typedef long long ll;
#define rep(i,n) for (int i=0;i < (int)(n);i++)

void solve(){
  int n;
  cin >> n;
  ll s;
  cin >> s;
  vector<ll> a(n);
  rep(i,n) a[i] = ll(n)-i;
  vector<ll> ans;
  for (int i = 0; i < n;i++){
    if (s - a[i] >= 0){
      ans.push_back(a[i]);
      s-=a[i];
    }
  }
  cout << ans.size() << "\n";
  for (auto e: ans){
    cout << e << " ";
  }
  cout << "\n";
  return;
}

  

int main(){
  int tt = 1;
  //cin >> tt;
  while(tt--){
	  solve();
  }
  return 0;
}