#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;

#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define rep(i,a,b) for (int i = (a); i < (b); ++i)

mt19937 rng(random_device {}());

int main()
{
    cin.tie(0)->sync_with_stdio(0);

    int Q;
    cin >> Q;
    set<int> s;
    vector<int> cnt(30);
    while(Q--){
        int q;
        cin >> q;
        if(q == 1){
            int x;
            cin >> x;
            if(!s.count(x)){
                s.insert(x);
                rep(i,0,30) if(x >> i & 1) cnt[i]++;
            }
        }
        else if(q == 2){
            int x;
            cin >> x;
            if(s.count(x)){
                s.erase(x);
                rep(i,0,30) if(x >> i & 1) cnt[i]--;
            }
        }
        else{
            if(s.empty()){
                cout << -1 << endl;
                continue;
            }
            int ans = 0;
            rep(i,0,30) if(cnt[i] == sz(s)) ans |= 1 << i;
            cout << ans << endl;
        }
    }

    return 0;
}