#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()
using ll=long long;
using pll=pair<ll,ll>;
using tll=tuple<ll,ll,ll>;
const ll INF=(1ll<<60);
template<class T> void chmin(T &a,T b){
    if(a>b){
        a=b;
    }
}
template<class T> void chmax(T &a,T b){
    if(a<b){
        a=b;
    }
}
int main(){
    vector<ll> v(30,0);
    set<ll> s;
    ll q;
    cin >> q;
    while(q--){
        ll p;
        cin >> p;
        if(p==1){
            ll x;
            cin >> x;
            if(s.count(x)) continue;
            s.insert(x);
            rep(i,30){
                if(x&(1<<i)){
                    v[i]++;
                }
            }
        }
        if(p==2){
            ll x;
            cin >> x;
            if(!s.count(x)) continue;
            s.erase(x);
            rep(i,30){
                if(x&(1<<i)){
                    v[i]--;
                }
            }
        }
        if(p==3){
            if(s.size()==0) cout << -1 << endl;
            else{
                ll sum=0;
                rep(i,30){
                    if(v[i]==s.size()) sum+=(1<<i);
                }
                cout << sum << endl;
            }
        }
    }
}