#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;
typedef unsigned long long ull;
//using mint = modint1000000007;
//using mint = modint998244353;



int main(){
  ll N, S;
  cin >> N >> S;

  vector<ll> v;
  while(true){
    ll x = min(N, S);
    v.push_back(x);
    N = x-1;
    S -= x;
    if(S == 0) break;
    if(N == 0) break;
  }

  if(S == 0){
    reverse(ALLOF(v));
    cout << v.size() << endl;
    rep(i,v.size()){
      if(i>0) cout << " ";
      cout << v[i];
    }
    cout << endl;
  }else{
    cout << -1 << endl;
  }
  
  
  return 0;
}