#include <bits/stdc++.h>
using namespace std;
int Q, I;
map<int, int> mset;
int main() {
  ios::sync_with_stdio(false);
  cin >> Q;
  mset[0] = 1;
  for (int i = 0; i < Q; ++i) {
    char c;
    int x;
    cin >> c >> x;
    if (c == '+') {
      mset[x]++;
    } else if (c == '-' && --mset[x] <= 0) {
      mset.erase(x);
    } else if (c == '?') {
      map<int, int>::iterator lo = mset.begin(), hi = --mset.end();
      int p = 1 << (30 - 1), dv = p;
      while (p > 0 && lo != hi) {
        if (x & p) {
          map<int, int>::iterator it = mset.lower_bound(dv);
          if (it != mset.begin() && (--it)->first >= lo->first) {
            hi = it;
            dv -= p / 2;
          } else {
            dv += p / 2;
          }
        } else {
          map<int, int>::iterator it = mset.lower_bound(dv);
          if (it != mset.end() && it->first <= hi->first) {
            lo = it;
            dv += p / 2;
          } else {
            dv -= p / 2;
          }
        }
        p /= 2;
      }
      cout << (x ^ lo->first) << '\n';
    }
  }
}

### Prompt

Develop a solution in CPP 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;
int Q, I;
map<int, int> mset;
int main() {
  ios::sync_with_stdio(false);
  cin >> Q;
  mset[0] = 1;
  for (int i = 0; i < Q; ++i) {
    char c;
    int x;
    cin >> c >> x;
    if (c == '+') {
      mset[x]++;
    } else if (c == '-' && --mset[x] <= 0) {
      mset.erase(x);
    } else if (c == '?') {
      map<int, int>::iterator lo = mset.begin(), hi = --mset.end();
      int p = 1 << (30 - 1), dv = p;
      while (p > 0 && lo != hi) {
        if (x & p) {
          map<int, int>::iterator it = mset.lower_bound(dv);
          if (it != mset.begin() && (--it)->first >= lo->first) {
            hi = it;
            dv -= p / 2;
          } else {
            dv += p / 2;
          }
        } else {
          map<int, int>::iterator it = mset.lower_bound(dv);
          if (it != mset.end() && it->first <= hi->first) {
            lo = it;
            dv += p / 2;
          } else {
            dv -= p / 2;
          }
        }
        p /= 2;
      }
      cout << (x ^ lo->first) << '\n';
    }
  }
}

```