#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < (n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int INF = 1001001001;
const ll LINF = 1001002003004005006ll;
//const int mod = 1000000007;
//const int mod = 998244353;

int main()
{
  int q;
  cin >> q;
  set<ll> st;
  vector<ll> bit(30);
  rep(qi, 0, q) {
    ll t, x;
    cin >> t;
    if (t == 1) {
      cin >> x;
      if (st.count(x)) continue;
      st.insert(x);
      rep(i, 0, 30) if (!(x>>i&1)) bit[i]++;
    }
    else if (t == 2) {
      cin >> x;
      if (st.count(x)) {
        st.erase(x);
        rep(i, 0, 30) if (!(x>>i&1)) bit[i]--;
      }
    }
    else {
      if (!st.size()) cout << -1 << endl;
      else {
        ll tmp = 1;
        ll ans = 0;
        rep(i, 0, 30) {
          if (!bit[i]) ans += tmp;
          tmp *= 2;
        }
        cout << ans << endl;
      }
    }
  }
  return 0;
}