#include <bits/stdc++.h>
using namespace std;
inline int in() {
  int x;
  scanf("%d", &x);
  return x;
}
inline long long inL() {
  long long x;
  scanf("%lld", &x);
  return x;
}
struct Node {
  Node* child[2];
  int cnt;
  Node() {
    cnt = 0;
    child[0] = NULL;
    child[1] = NULL;
  }
};
struct Trie {
  Node* root;
  Trie() { root = new Node(); }
  void insert(int x) {
    Node* cur = root;
    for (int i = 31; i >= 0; i--) {
      ++cur->cnt;
      int curBit = (x >> i) & 1;
      if (cur->child[curBit] == NULL) {
        cur->child[curBit] = new Node();
      }
      cur = cur->child[curBit];
    }
    ++cur->cnt;
  }
  void remove(int x) {
    Node* cur = root;
    for (int i = 31; i >= 0; i--) {
      --cur->cnt;
      int curBit = (x >> i) & 1;
      cur = cur->child[curBit];
    }
    --cur->cnt;
  }
  int query(int x) {
    Node* cur = root;
    int ret = 0;
    for (int i = 31; i >= 0; i--) {
      int curBit = (x >> i) & 1;
      if (cur->child[curBit ^ 1] != NULL && cur->child[curBit ^ 1]->cnt > 0) {
        ret |= (1 << i);
        cur = cur->child[curBit ^ 1];
      } else
        cur = cur->child[curBit];
    }
    return ret;
  }
};
int main() {
  int n = in();
  char c;
  int x;
  Trie trie;
  trie.insert(0);
  getchar();
  for (int i = 0; i < n; i++) {
    scanf("%c %d", &c, &x);
    if (c == '+') {
      trie.insert(x);
    } else if (c == '-') {
      trie.remove(x);
    } else if (c == '?') {
      cout << trie.query(x) << endl;
    }
    getchar();
  }
  return 0;
}

### Prompt

Your task is to create 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;
inline int in() {
  int x;
  scanf("%d", &x);
  return x;
}
inline long long inL() {
  long long x;
  scanf("%lld", &x);
  return x;
}
struct Node {
  Node* child[2];
  int cnt;
  Node() {
    cnt = 0;
    child[0] = NULL;
    child[1] = NULL;
  }
};
struct Trie {
  Node* root;
  Trie() { root = new Node(); }
  void insert(int x) {
    Node* cur = root;
    for (int i = 31; i >= 0; i--) {
      ++cur->cnt;
      int curBit = (x >> i) & 1;
      if (cur->child[curBit] == NULL) {
        cur->child[curBit] = new Node();
      }
      cur = cur->child[curBit];
    }
    ++cur->cnt;
  }
  void remove(int x) {
    Node* cur = root;
    for (int i = 31; i >= 0; i--) {
      --cur->cnt;
      int curBit = (x >> i) & 1;
      cur = cur->child[curBit];
    }
    --cur->cnt;
  }
  int query(int x) {
    Node* cur = root;
    int ret = 0;
    for (int i = 31; i >= 0; i--) {
      int curBit = (x >> i) & 1;
      if (cur->child[curBit ^ 1] != NULL && cur->child[curBit ^ 1]->cnt > 0) {
        ret |= (1 << i);
        cur = cur->child[curBit ^ 1];
      } else
        cur = cur->child[curBit];
    }
    return ret;
  }
};
int main() {
  int n = in();
  char c;
  int x;
  Trie trie;
  trie.insert(0);
  getchar();
  for (int i = 0; i < n; i++) {
    scanf("%c %d", &c, &x);
    if (c == '+') {
      trie.insert(x);
    } else if (c == '-') {
      trie.remove(x);
    } else if (c == '?') {
      cout << trie.query(x) << endl;
    }
    getchar();
  }
  return 0;
}

```