#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int,int>;

int main() {
    ll N,S;
    cin >> N >> S;
    vll ans(0,0);
    for (int i = N; i >= 1; i--) {
        if (i <= S) {
            ans.push_back(i);
            S -= i;
        }
    }
    ll as = ans.size();
    cout << as << endl;
    for (int i = as-1; i > 0; i--) {
        cout << ans[i] << ' ';
    }
    cout << ans[0] << endl;
}