human
Can you provide a Python program to print one integer — the maximum value of bitwise exclusive OR (XOR) of integer xi and some integer from the multiset A given the following:
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 , 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  — maximum among integers , , ,  and .
Solve the task in PYTHON3.
assistant
#Here is Python program to print one integer — the maximum value of bitwise exclusive OR (XOR) of integer xi and some integer from the multiset A.

#!/usr/bin/env pypy3
import sys

class BitTreeNode(object):
    __slots__ = ["left", "right", "count"]
    def __init__(self, cnt):
        self.left = None
        self.right = None
        self.count = cnt

class BitTree(object):
    
    def __init__(self):
        self.root = BitTreeNode(0)
        self.add(reversed(get_bits(0)))

    def add(self, bits):
        node = self.root
        node.count += 1
        for bit in bits:
            if bit:
                if not node.right:
                    node.right = BitTreeNode(1)
                else:
                    node.right.count += 1
                node = node.right
            else:
                if not node.left:
                    node.left = BitTreeNode(1)
                else:
                    node.left.count += 1
                node = node.left

    def remove(self, bits):
        node = self.root
        node.count -= 1
        for bit in bits:
            if bit == 0:
                node.left.count -= 1
                if node.left.count == 0:
                    node.left = None
                    return
                node = node.left
            else:
                node.right.count -= 1
                if node.right.count == 0:
                    node.right = None
                    return
                node = node.right
             
    def examine_xor(self, bits):
        best = 0
        node = self.root
        for i, bit in reversed(list(enumerate(bits))):
            assert node.count > 0
            if bit == 0:
                if node.right is not None:
                    best += 1 << i
                    node = node.right
                else:
                    node = node.left
            else:
                if node.left is not None:
                    best += 1 << i
                    node = node.left
                else:
                    node = node.right
        return best

    @classmethod
    def print_tree(cls, node, indent):
        print(" " * indent + "+", node.count)
        if...