#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main () {
    ll N, S;
    cin >> N >> S;
    vector<ll> ans;
    for (ll i = N; i > 0; i --) {
        if (S >= i) {
            ans.push_back(i);
            S -= i;
        }
    }
    cout << ans.size() << endl;
    reverse(ans.begin(), ans.end());
    for (auto a : ans) {
        cout << a << (a == ans.back() ? "" : " ");
    }
    cout << endl;
}