#include <bits/stdc++.h>
struct ctrie {
  struct ctrie* child[2];
  int cnt;
  ctrie() : cnt(0) { child[0] = child[1] = NULL; }
  struct ctrie* getchild(int index) {
    if (child[index] == NULL) {
      child[index] = new ctrie();
    }
    return child[index];
  }
  void insert(int val) {
    struct ctrie* curr = this;
    curr->cnt++;
    for (int k = 30; k >= 0; k--) {
      curr = curr->getchild((val >> k) & 1);
      curr->cnt++;
    }
  }
  void erase(int val) {
    struct ctrie* curr = this;
    curr->cnt--;
    for (int k = 30; k >= 0; k--) {
      curr = curr->getchild((val >> k) & 1);
      curr->cnt--;
    }
  }
  int query(int val) {
    struct ctrie* curr = this;
    int res = 0;
    for (int k = 30; k >= 0; k--) {
      int bit = (val >> k) & 1;
      if (curr->getchild(bit ^ 1)->cnt > 0) {
        curr = curr->getchild(bit ^ 1);
        res = res * 2 + 1;
      } else {
        curr = curr->getchild(bit);
        res = res * 2;
      }
    }
    return res;
  }
} root;
int main() {
  int Q;
  std::cin >> Q;
  root.insert(0);
  for (int i = 0; i < Q; i++) {
    std::string op;
    int val;
    std::cin >> op >> val;
    switch (op[0]) {
      case '+':
        root.insert(val);
        break;
      case '-':
        root.erase(val);
        break;
      case '?':
        std::cout << root.query(val) << std::endl;
        break;
    }
  }
  return 0;
}

### Prompt

Please create a solution in cpp 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>
struct ctrie {
  struct ctrie* child[2];
  int cnt;
  ctrie() : cnt(0) { child[0] = child[1] = NULL; }
  struct ctrie* getchild(int index) {
    if (child[index] == NULL) {
      child[index] = new ctrie();
    }
    return child[index];
  }
  void insert(int val) {
    struct ctrie* curr = this;
    curr->cnt++;
    for (int k = 30; k >= 0; k--) {
      curr = curr->getchild((val >> k) & 1);
      curr->cnt++;
    }
  }
  void erase(int val) {
    struct ctrie* curr = this;
    curr->cnt--;
    for (int k = 30; k >= 0; k--) {
      curr = curr->getchild((val >> k) & 1);
      curr->cnt--;
    }
  }
  int query(int val) {
    struct ctrie* curr = this;
    int res = 0;
    for (int k = 30; k >= 0; k--) {
      int bit = (val >> k) & 1;
      if (curr->getchild(bit ^ 1)->cnt > 0) {
        curr = curr->getchild(bit ^ 1);
        res = res * 2 + 1;
      } else {
        curr = curr->getchild(bit);
        res = res * 2;
      }
    }
    return res;
  }
} root;
int main() {
  int Q;
  std::cin >> Q;
  root.insert(0);
  for (int i = 0; i < Q; i++) {
    std::string op;
    int val;
    std::cin >> op >> val;
    switch (op[0]) {
      case '+':
        root.insert(val);
        break;
      case '-':
        root.erase(val);
        break;
      case '?':
        std::cout << root.query(val) << std::endl;
        break;
    }
  }
  return 0;
}

```