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(); StringBuilder sb = new StringBuilder(); HashSet current = new HashSet<>(); int[] counts = new int[30]; while (n-- > 0) { int type = sc.nextInt(); if (type == 1) { int x = sc.nextInt(); if (current.contains(x)) { continue; } current.add(x); for (int i = 0; i < 30; i++) { counts[i] += x % 2; x >>= 1; } } else if (type == 2) { int x = sc.nextInt(); if (!current.contains(x)) { continue; } current.remove(x); for (int i = 0; i < 30; i++) { counts[i] -= x % 2; x >>= 1; } } else { if (current.size() == 0) { sb.append("-1\n"); continue; } int ans = 0; for (int i = 0; i < 30; i++) { if (counts[i] == current.size()) { ans += (1 << i); } } 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(); } }