#include "bits/stdc++.h"
using namespace std;

#ifdef Nero
#include "Deb.h"
#else
#define deb(...)
#endif

signed main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int q;
  cin >> q;
  set<int> se; 
  multiset<int> ans; 
  auto ins = [&](int x) {
    auto it = se.insert(x).first;
    auto la = (it == se.begin() ? prev(se.end()) : prev(it)); 
    auto nx = (next(it) == se.end() ? se.begin() : next(it)); 
    if (se.size() > 1) {
      ans.insert(x ^ *la);
      ans.insert(x ^ *nx);       
    }
    if (se.size() > 2) {
      ans.erase(ans.find(*la ^ *nx));       
    }
  }; 
  auto rem = [&](int x) {
    auto it = se.find(x);
    auto la = (it == se.begin() ? prev(se.end()) : prev(it)); 
    auto nx = (next(it) == se.end() ? se.begin() : next(it)); 
    ans.insert(*la ^ *nx); 
    if (se.size() > 2) {
      ans.erase(ans.find(x ^ *la));
      ans.erase(ans.find(x ^ *nx)); 
    }
    se.erase(x); 
  }; 
  multiset<int> occ;
  map<int, int> freq; 
  while (q--) {
    int t;
    cin >> t;
    if (t == 1) {
      int x;
      cin >> x;
      if (freq.count(x)) {
        occ.erase(occ.find(freq[x]));        
      }
      freq[x]++; 
      occ.insert(freq[x]); 
      if (freq[x] == 1) {
        ins(x);         
      }
    } else if (t == 2) {
      int x;
      cin >> x; 
      occ.erase(occ.find(freq[x]));
      freq[x]--; 
      occ.insert(freq[x]); 
      if (freq[x] == 0) {
        rem(x);         
      }
    } else {
      if (*occ.rbegin() > 1) {
        cout << 0 << '\n';
      } else {
        cout << *ans.begin() << '\n';         
      }
    }
  }
  return 0;
}