//g++ 1.cpp -std=c++17 -O2 -I .
#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ld = long double;
 
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vld = vector<ld>;
using vvld = vector<vld>;
using vst = vector<string>;
using vvst = vector<vst>;
 
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define pq_big(T) priority_queue<T,vector<T>,less<T>>
#define pq_small(T) priority_queue<T,vector<T>,greater<T>>
#define all(a) a.begin(),a.end()
#define rep(i,start,end) for(ll i=start;i<(ll)(end);i++)
#define per(i,start,end) for(ll i=start;i>=(ll)(end);i--)
#define uniq(a) sort(all(a));a.erase(unique(all(a)),a.end())

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int q;
  cin>>q;

  map<int,int> mp;
  int sz=0;
  vi bt(30,0);

  while(q--){
    int op;cin>>op;

    if(op==1){
      int x;cin>>x;
      if(mp[x]==1)continue;
      mp[x]++;
      sz++;
      rep(i,0,30){
        if(x&(1<<i))bt[i]++;
      }
    }
    else if(op==2){
      int x;cin>>x;
      if(mp[x]==0)continue;
      mp[x]--;
      sz--;
      rep(i,0,30){
        if(x&(1<<i))bt[i]--;
      }
    }
    else{
      int ans=0;
      rep(i,0,30){
        if(bt[i]==sz){
          ans+=(1<<i);
        }
      }
      if(sz==0)ans=-1;
      cout<<ans<<endl;
    }
  }
}