typedef long long ll;
typedef long double ld;

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

signed main(){
    ll n;
    std::cin >> n;
    vector<ll> a(n);
    for (int i = 0; i < n; i++) {
        std::cin >> a[i];
    }
    map<ll,ll> val;
    set<ll> s;
    for (int i = 0; i < n; i++) {
        ll mi = a[i];
        for (auto e : s) {
            mi = min(mi, mi^val[e]);
        }
        
        if(mi!=0){
            s.insert(i);
            val[i] = mi;
        }else{
            vector<ll> res;
            res.push_back(i);
            for (auto e : s) {
                if((val[e]^a[i])<a[i]){
                    res.push_back(e);
                }
            }
            std::cout << res.size() << std::endl;
            for (auto e : res) {
                std::cout << e+1<<" ";
            }
            std::cout << std::endl;
            return 0;
        }
    }
};