#include <bits/stdc++.h>
using namespace std;

#ifdef _RUTHEN
#include "debug.hpp"
#else
#define show(...) true
#endif

using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); i++)
template <class T> using V = vector<T>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll N, S;
    cin >> N >> S;
    V<int> ans;
    for (int i = N; i >= 1; i--) {
        if (S >= i) {
            ans.push_back(i);
            S -= i;
        }
    }
    reverse(ans.begin(), ans.end());
    int M = ans.size();
    cout << M << '\n';
    rep(i, M) cout << ans[i] << " \n"[i == M - 1];
    return 0;
}