#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
using ll = long long;
#define all(x) x.begin(), x.end()
#define rep(i, n) for (int i = 0; i < n; i++)

int main(void)
{
    int n, s;
    cin >> n >> s;
    int summ = 0;
    vector<int> ans;

    for(int i = n; i > 0; i--){
        if(summ + i <= s){
            ans.push_back(i);
            summ += i;
        } 
    }
    reverse(all(ans));
    cout << ans.size() << endl;
    for(int i = 0; i < ans.size() - 1; i++){
        cout << ans[i] << ' ';
    }
    cout << ans.back() << endl;
    return 0;
}