#include <bits/stdc++.h>
using namespace std;
const int INF = 1 << 30, M = 32;
struct bst {
  bst *left, *right;
};
bst *mem;
int *memi;
void add_num(bst *p, int x, int t = INF) {
  if (!t) return;
  if (x & t) {
    if (p->right == NULL) {
      if (t >> 1 == 0) {
        p->right = (bst *)memi++;
        *(int *)p->right = 1;
      } else {
        p->right = mem++;
        p->right->right = NULL;
        p->right->left = NULL;
      }
    } else if (t >> 1 == 0)
      ++*(int *)p->right;
    add_num(p->right, x, t >> 1);
  } else {
    if (p->left == NULL) {
      if (t >> 1 == 0) {
        p->left = (bst *)memi++;
        *(int *)p->left = 1;
      } else {
        p->left = mem++;
        p->left->right = NULL;
        p->left->left = NULL;
      }
    } else if (t >> 1 == 0)
      ++*(int *)p->left;
    add_num(p->left, x, t >> 1);
  }
}
void delete_num(bst *p, int x, int t = INF) {
  if (!t) return;
  if (x & t) {
    delete_num(p->right, x, t >> 1);
    if (t >> 1 == 0) {
      if (*(int *)p->right == 1)
        p->right = NULL;
      else
        --*(int *)p->right;
    } else if (p->right->left == NULL && p->right->right == NULL)
      p->right = NULL;
  } else {
    delete_num(p->left, x, t >> 1);
    if (t >> 1 == 0) {
      if (*(int *)p->left == 1)
        p->left = NULL;
      else
        --*(int *)p->left;
    } else if (p->left->left == NULL && p->left->right == NULL)
      p->left = NULL;
  }
}
int max_xor_element(bst *p, int x, int t = INF) {
  if (!t) return 0;
  if (x & t) {
    if (p->left != NULL)
      return t + max_xor_element(p->left, x, t >> 1);
    else
      return max_xor_element(p->right, x, t >> 1);
  } else {
    if (p->right != NULL)
      return t + max_xor_element(p->right, x, t >> 1);
    else
      return max_xor_element(p->left, x, t >> 1);
  }
}
int main() {
  bst *root = new bst();
  root->right = NULL;
  root->left = NULL;
  int x, n, i, cur;
  char c;
  scanf("%d\n", &n);
  mem = (bst *)malloc(sizeof(bst) * n * 31);
  memi = (int *)malloc(sizeof(int) * n);
  add_num(root, 0);
  for (; n; n--) {
    scanf("%c %d\n", &c, &x);
    switch (c) {
      case '+':
        add_num(root, x);
        break;
      case '-':
        delete_num(root, x);
        break;
      case '?':
        cur = max_xor_element(root, x);
        printf("%d \n", cur);
        break;
    }
  }
  return 0;
}

### Prompt

Please provide a cpp coded solution to the problem described below:

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;
const int INF = 1 << 30, M = 32;
struct bst {
  bst *left, *right;
};
bst *mem;
int *memi;
void add_num(bst *p, int x, int t = INF) {
  if (!t) return;
  if (x & t) {
    if (p->right == NULL) {
      if (t >> 1 == 0) {
        p->right = (bst *)memi++;
        *(int *)p->right = 1;
      } else {
        p->right = mem++;
        p->right->right = NULL;
        p->right->left = NULL;
      }
    } else if (t >> 1 == 0)
      ++*(int *)p->right;
    add_num(p->right, x, t >> 1);
  } else {
    if (p->left == NULL) {
      if (t >> 1 == 0) {
        p->left = (bst *)memi++;
        *(int *)p->left = 1;
      } else {
        p->left = mem++;
        p->left->right = NULL;
        p->left->left = NULL;
      }
    } else if (t >> 1 == 0)
      ++*(int *)p->left;
    add_num(p->left, x, t >> 1);
  }
}
void delete_num(bst *p, int x, int t = INF) {
  if (!t) return;
  if (x & t) {
    delete_num(p->right, x, t >> 1);
    if (t >> 1 == 0) {
      if (*(int *)p->right == 1)
        p->right = NULL;
      else
        --*(int *)p->right;
    } else if (p->right->left == NULL && p->right->right == NULL)
      p->right = NULL;
  } else {
    delete_num(p->left, x, t >> 1);
    if (t >> 1 == 0) {
      if (*(int *)p->left == 1)
        p->left = NULL;
      else
        --*(int *)p->left;
    } else if (p->left->left == NULL && p->left->right == NULL)
      p->left = NULL;
  }
}
int max_xor_element(bst *p, int x, int t = INF) {
  if (!t) return 0;
  if (x & t) {
    if (p->left != NULL)
      return t + max_xor_element(p->left, x, t >> 1);
    else
      return max_xor_element(p->right, x, t >> 1);
  } else {
    if (p->right != NULL)
      return t + max_xor_element(p->right, x, t >> 1);
    else
      return max_xor_element(p->left, x, t >> 1);
  }
}
int main() {
  bst *root = new bst();
  root->right = NULL;
  root->left = NULL;
  int x, n, i, cur;
  char c;
  scanf("%d\n", &n);
  mem = (bst *)malloc(sizeof(bst) * n * 31);
  memi = (int *)malloc(sizeof(int) * n);
  add_num(root, 0);
  for (; n; n--) {
    scanf("%c %d\n", &c, &x);
    switch (c) {
      case '+':
        add_num(root, x);
        break;
      case '-':
        delete_num(root, x);
        break;
      case '?':
        cur = max_xor_element(root, x);
        printf("%d \n", cur);
        break;
    }
  }
  return 0;
}

```