import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int[] counts = new int[30];
        Set<Integer> store = new HashSet<>();
        StringBuilder sb = new StringBuilder();
        while (n-- > 0) {
            int type = sc.nextInt();
            if (type == 1) {
                int x = sc.nextInt();
                if (store.contains(x)) {
                    continue;
                }
                store.add(x);
                for (int i = 0; i < 30; i++) {
                    counts[i] += x % 2;
                    x >>= 1;
                }
            } else if (type == 2) {
                int x = sc.nextInt();
                if (!store.contains(x)) {
                    continue;
                }
                store.remove(x);
                for (int i = 0; i < 30; i++) {
                    counts[i] -= x % 2;
                    x >>= 1;
                }
            } else {
                if (store.size() == 0) {
                    sb.append("-1\n");
                    continue;
                }
                int ans = 0;
                for (int i = 0; i < 30; i++) {
                    if (counts[i] == store.size()) {
                        ans += (1 << i);
                    }
                }
                sb.append(ans).append("\n");
            }
        }
        System.out.print(sb);
    }
}
class Scanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (Exception e) {
            
        }
    }
    
    public int nextInt() {
        return Integer.parseInt(next());
    }
    
    public long nextLong() {
        return Long.parseLong(next());
    }
    
    public double nextDouble() {
        return Double.parseDouble(next());
    }
    
    public String next() {
        try {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            return st.nextToken();
        }
    }
    
}