#include <bits/stdc++.h>
using namespace std;
const int maxn = 3 * 1e6 + 7;
struct Tree {
  int Next[maxn][2];
  int val[maxn];
  int L, root;
  void init() {
    L = 0;
    root = newnode();
  }
  int newnode() {
    for (int i = 0; i < 2; i++) Next[L][i] = -1;
    val[L++] = 0;
    return L - 1;
  }
  void insert(int va) {
    int u = root, v;
    for (int i = 29; i >= 0; i--) {
      v = (va & (1 << i)) ? 1 : 0;
      if (Next[u][v] == -1) Next[u][v] = newnode();
      u = Next[u][v];
      val[u]++;
    }
  }
  void Delete(int va) {
    int u = root, v;
    for (int i = 29; i >= 0; i--) {
      v = (va & (1 << i)) ? 1 : 0;
      u = Next[u][v];
      val[u]--;
    }
  }
  int query(int x) {
    int u = root, v;
    for (int i = 29; i >= 0; i--) {
      v = (x & (1 << i)) ? 1 : 0;
      if (v == 1) {
        if (Next[u][0] != -1 && val[Next[u][0]])
          u = Next[u][0];
        else {
          u = Next[u][1];
          x ^= (1 << i);
        }
      } else {
        if (Next[u][1] != -1 && val[Next[u][1]]) {
          u = Next[u][1];
          x ^= (1 << i);
        } else
          u = Next[u][0];
      }
    }
    return x;
  }
} T;
int main() {
  int q;
  T.init();
  T.insert(0);
  scanf("%d", &q);
  while (q--) {
    string op;
    int v;
    cin >> op >> v;
    if (op == "+") T.insert(v);
    if (op == "-") T.Delete(v);
    if (op == "?") printf("%d\n", T.query(v));
  }
}

### 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;
const int maxn = 3 * 1e6 + 7;
struct Tree {
  int Next[maxn][2];
  int val[maxn];
  int L, root;
  void init() {
    L = 0;
    root = newnode();
  }
  int newnode() {
    for (int i = 0; i < 2; i++) Next[L][i] = -1;
    val[L++] = 0;
    return L - 1;
  }
  void insert(int va) {
    int u = root, v;
    for (int i = 29; i >= 0; i--) {
      v = (va & (1 << i)) ? 1 : 0;
      if (Next[u][v] == -1) Next[u][v] = newnode();
      u = Next[u][v];
      val[u]++;
    }
  }
  void Delete(int va) {
    int u = root, v;
    for (int i = 29; i >= 0; i--) {
      v = (va & (1 << i)) ? 1 : 0;
      u = Next[u][v];
      val[u]--;
    }
  }
  int query(int x) {
    int u = root, v;
    for (int i = 29; i >= 0; i--) {
      v = (x & (1 << i)) ? 1 : 0;
      if (v == 1) {
        if (Next[u][0] != -1 && val[Next[u][0]])
          u = Next[u][0];
        else {
          u = Next[u][1];
          x ^= (1 << i);
        }
      } else {
        if (Next[u][1] != -1 && val[Next[u][1]]) {
          u = Next[u][1];
          x ^= (1 << i);
        } else
          u = Next[u][0];
      }
    }
    return x;
  }
} T;
int main() {
  int q;
  T.init();
  T.insert(0);
  scanf("%d", &q);
  while (q--) {
    string op;
    int v;
    cin >> op >> v;
    if (op == "+") T.insert(v);
    if (op == "-") T.Delete(v);
    if (op == "?") printf("%d\n", T.query(v));
  }
}

```