#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <atcoder/modint>

using namespace std;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
#define rep(i,n) for(int i=0; i<(int)(n); i++)


const i64 INF = 1001001001001001001;
using modint = atcoder::static_modint<998244353>;


int main(){
    i64 N,S; cin >> N >> S;
    vector<i64> res;
    for(i64 i=N; i>=1; i--){
        if(i <= S){
            res.push_back(i);
            S -= i;
        }
    }
    reverse(res.begin(), res.end());
    cout << res.size() << '\n';
    rep(i,res.size()){
        if(i) cout << ' ';
        cout << res[i];
    }
    cout << '\n';
    return 0;
}


struct ios_do_not_sync{
    ios_do_not_sync(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }
} ios_do_not_sync_instance;