#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,m,n) for(int i=m; i<n; ++i)
#define repl(i,m,n) for(ll i=m; i<n; ++i)

int main(){
    multiset<int> st;
    vector<int> cnt(30,0);

    int Q;
    cin >> Q;

    rep(q, 0, Q){
        int type;
        cin >> type;

        if(type == 1){
            int x;
            cin >> x;
            if(st.find(x) != st.end()) continue;
            st.insert(x);
            rep(i, 0, 30){
                if(x & (1<<i)) cnt[i]++;
            }
        }else if(type == 2){
            int x;
            cin >> x;
            auto itr = st.find(x);
            if(itr == st.end()) continue;
            st.erase(itr);
            rep(i, 0, 30){
                if(x & (1<<i)) cnt[i]--;
            }
        }else{
            int ans = 0;
            int sz = st.size();
            if(sz == 0){
                cout << -1 << endl;
            }else{
                rep(i, 0, 30){
                    if(cnt[i] == sz){
                        ans += (1<<i);
                    }
                }
                cout << ans << endl;
            }
        }
    }

    return 0;
}