#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
typedef long long ll;

int main()
{
    int n;
    ll s;
    cin >> n >> s;
    vector<int> a;
    for (int i = n; i > 0; i--)
    {
        if (i <= s)
        {
            a.push_back(i);
            s -= i;
        }
    }
    reverse(a.begin(), a.end());
    cout << a.size() << endl;
    for (int i : a)
    {
        cout << i << " ";
    }
    cout << endl;
}