using static System.Math;
using System.Collections.Generic;
using System.Linq;
using System;

public class Hello
{
    static void Main()
    {
        var q = int.Parse(Console.ReadLine().Trim());
        getAns(q);
    }
    static void getAns(int q)
    {
        var b = new int[30];
        var hs = new HashSet<int>();
        for (int i = 0; i < q; i++)
        {
            string[] line = Console.ReadLine().Trim().Split(' ');
            if (line[0] == "1")
            {
                var x = int.Parse(line[1]);
                if (hs.Add(x))
                {
                    for (int j = 0; j < 30; j++)
                    {
                        if (((x >> j) & 1) == 1) b[j]++;
                    }
                }
            }
            else if (line[0] == "2")
            {
                var x = int.Parse(line[1]);
                if (hs.Remove(x))
                {
                    for (int j = 0; j < 30; j++)
                    {
                        if (((x >> j) & 1) == 1) b[j]--;
                    }
                }
            }
            else
            {
                var hsc = hs.Count;
                if (hsc == 0) { Console.WriteLine(-1); continue; }
                var ans = 0;
                for (int j = 0; j < 30; j++)
                {
                    if (b[j] == hsc) ans |= 1 << j;
                }
                Console.WriteLine(ans);
            }
        }
    }
}