#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <map>
#include <queue>
#include <set>
#include <cstring>
#include <vector>

using namespace std;
typedef long long ll;

int main() {
  int Q;
  cin >> Q;
  set<int> S;
  int counter[32];
  memset(counter, 0, sizeof(counter));

  for (int i = 0; i < Q; ++i) {
    int type, x;
    cin >> type;

    if (type == 1) {
      cin >> x;

      if (not S.count(x)) {
        S.insert(x);
        for (int i = 0; i < 32; ++i) {
          if ((x >> i) & 1) {
            counter[i] += 1;
          }
        }
      }
    } else if (type == 2) {
      cin >> x;

      if (S.count(x)) {
        S.erase(x);
        for (int i = 0; i < 32; ++i) {
          if ((x >> i) & 1) {
            counter[i] -= 1;
          }
        }
      }
    } else {
      if (S.empty()) {
        cout << -1 << endl;
      } else {
        ll val = 0;
        for (ll i = 0; i < 32; ++i) {
          if (counter[i] < S.size()) continue;

          if (counter[i] > 0) {
            val += pow(2, i);
          }
        }

        cout << val << endl;
      }
    }
  }

  return 0;
}