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

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        HashSet<Integer> exist = new HashSet<>();
        int[] counts = new int[30];
        StringBuilder sb = new StringBuilder();
        while (n-- > 0) {
            int type = sc.nextInt();
            if (type == 1) {
                int x = sc.nextInt();
                if (exist.contains(x)) {
                    continue;
                }
                exist.add(x);
                for (int i = 0; i < 30; i++) {
                    counts[i] += x % 2;
                    x >>= 1;
                }
            } else if (type == 2) {
                int x = sc.nextInt();
                if (!exist.contains(x)) {
                    continue;
                }
                exist.remove(x);
                for (int i = 0; i < 30; i++) {
                    counts[i] -= x % 2;
                    x >>= 1;
                }
            } else {
                if (exist.size() == 0) {
                    sb.append("-1\n");
                    continue;
                }
                int ans = 0;
                for (int i = 29; i >= 0; i--) {
                    ans <<= 1;
                    if (counts[i] == exist.size()) {
                        ans++;
                    }
                }
                sb.append(ans).append("\n");
            }
        }
        System.out.print(sb);
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}