#include <bits/stdc++.h>
using namespace std;
struct TrieNode {
  int cnt;
  TrieNode *room[2];
  TrieNode() : cnt(0) { memset(room, 0, sizeof(room)); }
  ~TrieNode() {
    if (room[0]) delete room[0];
    if (room[1]) delete room[1];
  }
  void ins(int d, int n) {
    cnt++;
    if (n < 0) return;
    int t = d & (1 << n) ? 1 : 0;
    if (!room[t]) room[t] = new TrieNode();
    room[t]->ins(d, n - 1);
  }
  void rm(int d, int n) {
    cnt--;
    if (n < 0) return;
    int t = d & (1 << n) ? 1 : 0;
    room[t]->rm(d, n - 1);
    if (room[t]->cnt == 0) {
      delete room[t];
      room[t] = nullptr;
    }
  }
  int find(int d, int n) {
    if (n < 0) return 0;
    int t = d & (1 << n) ? 1 : 0;
    if (room[t ^ 1])
      return (1 << n) + room[t ^ 1]->find(d, n - 1);
    else
      return room[t]->find(d, n - 1);
  }
};
int main() {
  string type;
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, d;
  cin >> n;
  TrieNode *tn = new TrieNode();
  tn->ins(0, 29);
  for (int i = 0; i < n; i++) {
    cin >> type >> d;
    if (type == "+")
      tn->ins(d, 29);
    else if (type == "-")
      tn->rm(d, 29);
    else
      cout << tn->find(d, 29) << "\n";
  }
  delete tn;
  return 0;
}

### Prompt

Your challenge is to write 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>
using namespace std;
struct TrieNode {
  int cnt;
  TrieNode *room[2];
  TrieNode() : cnt(0) { memset(room, 0, sizeof(room)); }
  ~TrieNode() {
    if (room[0]) delete room[0];
    if (room[1]) delete room[1];
  }
  void ins(int d, int n) {
    cnt++;
    if (n < 0) return;
    int t = d & (1 << n) ? 1 : 0;
    if (!room[t]) room[t] = new TrieNode();
    room[t]->ins(d, n - 1);
  }
  void rm(int d, int n) {
    cnt--;
    if (n < 0) return;
    int t = d & (1 << n) ? 1 : 0;
    room[t]->rm(d, n - 1);
    if (room[t]->cnt == 0) {
      delete room[t];
      room[t] = nullptr;
    }
  }
  int find(int d, int n) {
    if (n < 0) return 0;
    int t = d & (1 << n) ? 1 : 0;
    if (room[t ^ 1])
      return (1 << n) + room[t ^ 1]->find(d, n - 1);
    else
      return room[t]->find(d, n - 1);
  }
};
int main() {
  string type;
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, d;
  cin >> n;
  TrieNode *tn = new TrieNode();
  tn->ins(0, 29);
  for (int i = 0; i < n; i++) {
    cin >> type >> d;
    if (type == "+")
      tn->ins(d, 29);
    else if (type == "-")
      tn->rm(d, 29);
    else
      cout << tn->find(d, 29) << "\n";
  }
  delete tn;
  return 0;
}

```