#include <bits/stdc++.h>
//#include <atcoder/modint>

using namespace std;
//using namespace atcoder;
using ll = long long;
//using mint = modint998244353;

int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);

    /*
       Xを1に初期化
       あとはYと一致するように左シフト+1
       X=YならYes
       Yの末尾のbitが1でないならNo
    */

    ll N, X, Y, Z;
    cin >> N >> X >> Y;
    Z = X;
    if (X == Y){
        cout << 0 << endl;
        cout << endl;
        return 0;
    }
    if (Y % 2 == 0){
        cout << -1 << endl;
        return 0;
    }
    vector<ll> ans;
    //1に初期化
    X = 1;
    ans.push_back(N);
    ll p=-1, z;
    for (int i=N-1; i>=0; i--){
        if ((Y>>i) & 1){
            if (p == -1) p = i;
            else{
                z = p-i;
                ans.push_back(z);
                p = i;
            }
        }
    }
    for (auto x : ans){
        Z = (Z<<x)+1;
        Z %= (1LL<<N);
    }
    assert(Z == Y);
    cout << ans.size() << endl;
    for (auto x : ans) cout << x << " ";
    cout << endl;

    return 0;
}