#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); ++i)

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