#include <bits/stdc++.h>
using namespace std;
struct Trie {
  Trie *child[2];
  int num;
  Trie() {
    num = 0;
    child[0] = child[1] = NULL;
  }
};
Trie *root = new Trie;
void insert_trie(Trie *node, int x, int p2) {
  if (p2 == -1) {
    node->num++;
    return;
  }
  int bit = (x >> p2) & 1;
  if (node->child[bit] == NULL) {
    node->child[bit] = new Trie;
  }
  insert_trie(node->child[bit], x, p2 - 1);
}
bool delete_trie(Trie *node, int x, int p2) {
  if (p2 == -1) {
    node->num--;
  } else {
    int bit = (x >> p2) & 1;
    if (delete_trie(node->child[bit], x, p2 - 1)) {
      node->child[bit] = NULL;
    }
  }
  if (node->num == 0 && node->child[0] == NULL && node->child[1] == NULL &&
      node != root) {
    delete node;
    return 1;
  }
  return 0;
}
int query(Trie *node, int x, int p2) {
  if (p2 == -1) {
    return 0;
  }
  int bit = ((x >> p2) & 1) ^ 1;
  if (node->child[bit] != NULL) {
    return (1 << p2) + query(node->child[bit], x, p2 - 1);
  }
  return query(node->child[bit ^ 1], x, p2 - 1);
}
int main() {
  insert_trie(root, 0, 30);
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    char c;
    int x;
    scanf(" %c %d", &c, &x);
    if (c == '+') {
      insert_trie(root, x, 30);
    } else if (c == '-') {
      delete_trie(root, x, 30);
    } else {
      printf("%d\n", query(root, x, 30));
    }
  }
  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>
using namespace std;
struct Trie {
  Trie *child[2];
  int num;
  Trie() {
    num = 0;
    child[0] = child[1] = NULL;
  }
};
Trie *root = new Trie;
void insert_trie(Trie *node, int x, int p2) {
  if (p2 == -1) {
    node->num++;
    return;
  }
  int bit = (x >> p2) & 1;
  if (node->child[bit] == NULL) {
    node->child[bit] = new Trie;
  }
  insert_trie(node->child[bit], x, p2 - 1);
}
bool delete_trie(Trie *node, int x, int p2) {
  if (p2 == -1) {
    node->num--;
  } else {
    int bit = (x >> p2) & 1;
    if (delete_trie(node->child[bit], x, p2 - 1)) {
      node->child[bit] = NULL;
    }
  }
  if (node->num == 0 && node->child[0] == NULL && node->child[1] == NULL &&
      node != root) {
    delete node;
    return 1;
  }
  return 0;
}
int query(Trie *node, int x, int p2) {
  if (p2 == -1) {
    return 0;
  }
  int bit = ((x >> p2) & 1) ^ 1;
  if (node->child[bit] != NULL) {
    return (1 << p2) + query(node->child[bit], x, p2 - 1);
  }
  return query(node->child[bit ^ 1], x, p2 - 1);
}
int main() {
  insert_trie(root, 0, 30);
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    char c;
    int x;
    scanf(" %c %d", &c, &x);
    if (c == '+') {
      insert_trie(root, x, 30);
    } else if (c == '-') {
      delete_trie(root, x, 30);
    } else {
      printf("%d\n", query(root, x, 30));
    }
  }
  return 0;
}

```