#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:1000000000")
using namespace std;
const int BIT_SIZE = 30;
class Node {
 public:
  Node* children[2];
  int n_terminal;
  Node() : n_terminal(0) { children[0] = children[1] = NULL; }
  void change(int num_bits[BIT_SIZE], int index, int mod) {
    n_terminal += mod;
    int bit = num_bits[index];
    if (index == BIT_SIZE) return;
    if (children[bit] == NULL) children[bit] = new Node();
    children[bit]->change(num_bits, index + 1, mod);
  }
  int max_xor(int num_bits[BIT_SIZE], int index) {
    if (index == BIT_SIZE) return 0;
    int size[2] = {0, 0};
    for (int i = 0; i < 2; i++)
      if (children[i]) size[i] = children[i]->n_terminal;
    int needed_bit = (num_bits[index] + 1) % 2;
    if (size[needed_bit] > 0)
      return ((1 << (BIT_SIZE - index - 1)) +
              children[needed_bit]->max_xor(num_bits, index + 1));
    else
      return children[num_bits[index]]->max_xor(num_bits, index + 1);
  }
};
int main() {
  int n_queries = 0;
  cin >> n_queries;
  Node* root = new Node();
  int default_num_bits[BIT_SIZE] = {};
  root->change(default_num_bits, 0, 1);
  for (int j = 0; j < n_queries; j++) {
    char type = 0;
    int n = 0;
    cin >> type >> n;
    int num_bits[BIT_SIZE] = {};
    int curr_filled = 0;
    while (curr_filled < BIT_SIZE) {
      num_bits[BIT_SIZE - curr_filled - 1] = n % 2;
      n /= 2;
      curr_filled++;
    }
    if (type == '+')
      root->change(num_bits, 0, 1);
    else if (type == '-')
      root->change(num_bits, 0, -1);
    else
      cout << root->max_xor(num_bits, 0) << "\n";
  }
  return 0;
}

### Prompt

Please formulate a Cpp solution to the following problem:

Author has gone out of the stories about Vasiliy, so here is just a formal task description.

You are given q queries and a multiset A, initially containing only integer 0. There are three types of queries:

  1. "+ x" — add integer x to multiset A.
  2. "- x" — erase one occurrence of integer x from multiset A. It's guaranteed that at least one x is present in the multiset A before this query.
  3. "? x" — you are given integer x and need to compute the value <image>, i.e. the maximum value of bitwise exclusive OR (also know as XOR) of integer x and some integer y from the multiset A.



Multiset is a set, where equal elements are allowed.

Input

The first line of the input contains a single integer q (1 ≤ q ≤ 200 000) — the number of queries Vasiliy has to perform.

Each of the following q lines of the input contains one of three characters '+', '-' or '?' and an integer xi (1 ≤ xi ≤ 109). It's guaranteed that there is at least one query of the third type.

Note, that the integer 0 will always be present in the set A.

Output

For each query of the type '?' print one integer — the maximum value of bitwise exclusive OR (XOR) of integer xi and some integer from the multiset A.

Example

Input

10
+ 8
+ 9
+ 11
+ 6
+ 1
? 3
- 8
? 3
? 8
? 11


Output

11
10
14
13

Note

After first five operations multiset A contains integers 0, 8, 9, 11, 6 and 1.

The answer for the sixth query is integer <image> — maximum among integers <image>, <image>, <image>, <image> and <image>.

### Response

```cpp
#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:1000000000")
using namespace std;
const int BIT_SIZE = 30;
class Node {
 public:
  Node* children[2];
  int n_terminal;
  Node() : n_terminal(0) { children[0] = children[1] = NULL; }
  void change(int num_bits[BIT_SIZE], int index, int mod) {
    n_terminal += mod;
    int bit = num_bits[index];
    if (index == BIT_SIZE) return;
    if (children[bit] == NULL) children[bit] = new Node();
    children[bit]->change(num_bits, index + 1, mod);
  }
  int max_xor(int num_bits[BIT_SIZE], int index) {
    if (index == BIT_SIZE) return 0;
    int size[2] = {0, 0};
    for (int i = 0; i < 2; i++)
      if (children[i]) size[i] = children[i]->n_terminal;
    int needed_bit = (num_bits[index] + 1) % 2;
    if (size[needed_bit] > 0)
      return ((1 << (BIT_SIZE - index - 1)) +
              children[needed_bit]->max_xor(num_bits, index + 1));
    else
      return children[num_bits[index]]->max_xor(num_bits, index + 1);
  }
};
int main() {
  int n_queries = 0;
  cin >> n_queries;
  Node* root = new Node();
  int default_num_bits[BIT_SIZE] = {};
  root->change(default_num_bits, 0, 1);
  for (int j = 0; j < n_queries; j++) {
    char type = 0;
    int n = 0;
    cin >> type >> n;
    int num_bits[BIT_SIZE] = {};
    int curr_filled = 0;
    while (curr_filled < BIT_SIZE) {
      num_bits[BIT_SIZE - curr_filled - 1] = n % 2;
      n /= 2;
      curr_filled++;
    }
    if (type == '+')
      root->change(num_bits, 0, 1);
    else if (type == '-')
      root->change(num_bits, 0, -1);
    else
      cout << root->max_xor(num_bits, 0) << "\n";
  }
  return 0;
}

```