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

long long n, s;
vector<long long> v;

int main() {    
    cin >> n >> s;

    for (long long i = n; i > 0; i--) {
        if (i <= s) {
            v.push_back(i);
            s -= i;
        }
    }

    long long k = v.size();

    cout << k << endl;

    for (long long i = 0; i < k; i++) {
        cout << v[k - 1 - i];

        if (i < k - 1)
            cout << " ";
    }
    cout << endl;
}