#include <bits/stdc++.h>
using namespace std;
const int MAXBIT = 29;
class node {
 public:
  int count;
  node *n0, *n1;
  node() : count(0), n0(0), n1(0) {}
};
class root {
 public:
  node rn;
  void insert(int x) {
    node *n = &rn;
    n->count++;
    for (int m = 1 << MAXBIT; m > 0; m >>= 1) {
      if (x & m) {
        if (n->n1) {
          n = n->n1;
        } else {
          n = n->n1 = new node;
        }
      } else {
        if (n->n0) {
          n = n->n0;
        } else {
          n = n->n0 = new node;
        }
      }
      n->count++;
    }
  }
  void remove(int x) {
    node *n = &rn;
    n->count--;
    for (int m = 1 << MAXBIT; m > 0; m >>= 1) {
      if (x & m) {
        n = n->n1;
      } else {
        n = n->n0;
      }
      n->count--;
    }
  }
  int maxor(int x) {
    int a = 0;
    node *n = &rn;
    for (int m = 1 << MAXBIT; m > 0; m >>= 1) {
      if (x & m) {
        if (!n->n0) {
          n->n0 = new node;
        }
        if (n->n0->count > 0) {
          n = n->n0;
          a += m;
        } else {
          n = n->n1;
        }
      } else {
        if (!n->n1) {
          n->n1 = new node;
        }
        if (n->n1->count > 0) {
          n = n->n1;
          a += m;
        } else {
          n = n->n0;
        }
      }
    }
    return a;
  }
};
int main(int argc, char **argv) {
  int q;
  cin >> q;
  root r;
  r.insert(0);
  for (int i = 0; i < q; i++) {
    string op;
    int x;
    cin >> op >> x;
    switch (op[0]) {
      case '+':
        r.insert(x);
        break;
      case '-':
        r.remove(x);
        break;
      case '?':
        cout << r.maxor(x) << endl;
        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 MAXBIT = 29;
class node {
 public:
  int count;
  node *n0, *n1;
  node() : count(0), n0(0), n1(0) {}
};
class root {
 public:
  node rn;
  void insert(int x) {
    node *n = &rn;
    n->count++;
    for (int m = 1 << MAXBIT; m > 0; m >>= 1) {
      if (x & m) {
        if (n->n1) {
          n = n->n1;
        } else {
          n = n->n1 = new node;
        }
      } else {
        if (n->n0) {
          n = n->n0;
        } else {
          n = n->n0 = new node;
        }
      }
      n->count++;
    }
  }
  void remove(int x) {
    node *n = &rn;
    n->count--;
    for (int m = 1 << MAXBIT; m > 0; m >>= 1) {
      if (x & m) {
        n = n->n1;
      } else {
        n = n->n0;
      }
      n->count--;
    }
  }
  int maxor(int x) {
    int a = 0;
    node *n = &rn;
    for (int m = 1 << MAXBIT; m > 0; m >>= 1) {
      if (x & m) {
        if (!n->n0) {
          n->n0 = new node;
        }
        if (n->n0->count > 0) {
          n = n->n0;
          a += m;
        } else {
          n = n->n1;
        }
      } else {
        if (!n->n1) {
          n->n1 = new node;
        }
        if (n->n1->count > 0) {
          n = n->n1;
          a += m;
        } else {
          n = n->n0;
        }
      }
    }
    return a;
  }
};
int main(int argc, char **argv) {
  int q;
  cin >> q;
  root r;
  r.insert(0);
  for (int i = 0; i < q; i++) {
    string op;
    int x;
    cin >> op >> x;
    switch (op[0]) {
      case '+':
        r.insert(x);
        break;
      case '-':
        r.remove(x);
        break;
      case '?':
        cout << r.maxor(x) << endl;
        break;
    }
  }
  return 0;
}

```