#define _USE_MATH_DEFINES
#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<string>
#include<iomanip>
#include<numeric>
#include<queue>
#include<deque>
#include<stack>
#include<set>
#include<map>
#include<random>
#include<bitset>
#include<cassert>
using namespace std;
typedef long long ll;
const int mod=1e9+7;
const int dx[]={1,0,0,-1},dy[]={0,1,-1,0};
int main(){
	int n;
	ll s;
	cin>>n>>s;
	vector<int>ans;
	for(int i=n;i>=1;i--){
		if(s>=i){
			s-=i;
			ans.push_back(i);
		}
	}
	reverse(ans.begin(),ans.end());
	cout<<ans.size()<<endl;
	for(int i=0;i<ans.size();i++)
		cout<<ans[i]<<(i+1==ans.size()?'\n':' ');
}