#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  long long S;
  cin >> N >> S;
  vector<int> A;
  for (int i = N; i >= 1; i--){
    if (S >= i){
      A.push_back(i);
      S -= i;
    }
  }
  reverse(A.begin(), A.end());
  int K = A.size();
  cout << K << endl;
  for (int i = 0; i < K; i++){
    cout << A[i];
    if (i < K - 1){
      cout << ' ';
    }
  }
  cout << endl;
}