#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
#include <deque>
#include <cmath>
#include <iomanip>
#include <set>
#include <map>
using namespace std;
using ll = long long;
using ld = long double;

int main(){
    int q; cin >> q;
    set<int> s;
    vector<int> cnt(32, 0);
    while(q--){
        int op; cin >> op;
        if(op == 1){
            int x; cin >> x;
            if(s.count(x) == 0){
                s.emplace(x);
                for(int i = 30; i >= 0; i--){
                    if((x >> i) & 1) cnt[i]++;
                }
            }
        }else if(op == 2){
            int x; cin >> x;
            if(s.count(x) == 1){
                s.erase(x);
                for(int i = 30; i >= 0; i--){
                    if((x >> i) & 1) cnt[i]--;
                }
            }
        }else{
            int ans = 0;
            for(int i = 30; i >= 0; i--){
                if(cnt[i] == s.size()) ans |= 1 << i;
            }
            if(s.size() == 0) ans = -1;
            cout << ans << '\n';
        }
    }
    return 0;
}