/* -*- coding: utf-8 -*-
 *
 * 2195.cc:  No.2195 AND Set - yukicoder
 */

#include<cstdio>
#include<unordered_set>
#include<algorithm>
 
using namespace std;

/* constant */

const int BN = 30;

/* typedef */

/* global variables */

int cs[BN][2];

/* subroutines */

/* main */

int main() {
  int qn;
  scanf("%d", &qn);

  unordered_set<int> xs;
  
  while (qn--) {
    int op;
    scanf("%d", &op);

    if (op == 1) {
      int x;
      scanf("%d", &x);

      if (! xs.count(x)) {
	xs.insert(x);
	for (int i = 0; i < BN; i++)
	  cs[i][(x >> i) & 1]++;
      }
    }
    else if (op == 2) {
      int x;
      scanf("%d", &x);

      if (xs.count(x)) {
	xs.erase(x);
	for (int i = 0; i < BN; i++)
	  cs[i][(x >> i) & 1]--;
      }
    }
    else {
      if (xs.empty()) puts("-1");
      else {
	int s = 0;
	for (int i = 0, bi = 1; i < BN; i++, bi <<= 1)
	  if (cs[i][0] == 0 && cs[i][1] > 0) s |= bi;
	printf("%d\n", s);
      }
    }
  }

  return 0;
}