#include <iostream>
#include <set>

using namespace std;
int main()
{
    unsigned int q, i, t;
    int j;
    long x;
    unsigned int c[31] = {0};
    set<long> s;
    cin >> q;
    for (i = 0; i < q; i++)
    {
        cin >> t;
        switch (t)
        {
        case 1:
            cin >> x;
            if (s.count(x) == 0)
            {
                s.insert(x);
                for (j = 0; j < 31; j++)
                    if ((1 << j) & x)
                        c[j]++;
            }
            break;
        case 2:
            cin >> x;
            if (s.count(x) != 0)
            {
                s.erase(x);
                for (j = 0; j < 31; j++)
                    if ((1 << j) & x)
                        c[j]--;
            }
            break;

        default:
            if (s.size() > 0)
            {
                x=0;
                for(j=30;j>=0;j--)
                {
                    x=x<<1;
                    if(c[j]==s.size())
                        x++;
                }
            }
            else
                x = -1;
            cout << x << endl;
            break;
        }
    }
}