#include <bits/stdc++.h>   using namespace std;   typedef struct node {     struct node* b[3];     int flag[3];   } node;   node* root;   vector<int> ans;   int bit[32], bit_n[32];   void calc(int u) {     memset(bit_n, 0, sizeof(bit_n));     memset(bit, 0, sizeof(bit));     int j = 0, num;     for (num = u; num > 0; num = num / 2) bit_n[j++] = num % 2;     for (int i = 0; i < 32; i++) bit[i] = bit_n[31 - i];   }   void insert(int u) {     node* head;     head = root;     calc(u);     for (int i = 0; i < 32; i++) {       if (head->b[bit[i]] == NULL) {         node* temp;         temp = (node*)malloc(sizeof(node));         for (int j = 0; j < 3; j++) temp->b[j] = NULL, temp->flag[j] = 0;         head->b[bit[i]] = temp;       }       head->flag[bit[i]]++;       head = head->b[bit[i]];     }     return;   }   void del(int u) {     node* head;     head = root;     calc(u);     for (int i = 0; i < 32; i++) {       head->flag[bit[i]]--;       head = head->b[bit[i]];     }     return;   }   void search(int u) {     calc(u);     node* head;     head = root;     for (int i = 0; i < 32; i++) {       if (bit[i] == 1) {         if (head->flag[0])           ans.push_back(1), head = head->b[0];         else           ans.push_back(0), head = head->b[1];       } else {         if (head->flag[1])           ans.push_back(1), head = head->b[1];         else           ans.push_back(0), head = head->b[0];       }     }   }   int main() {     root = (node*)malloc(sizeof(node));     for (int i = 0; i < 3; i++) root->b[i] = NULL, root->flag[i] = 0;     int n;     cin >> n;     insert(0);     char a;     int num;     for (int i = 0; i < n; i++) {       int calc = 0;       cin >> a >> num;       if (a ==  + )         insert(num);       else if (a ==  - )         del(num);       else {         ans.clear();         search(num);         for (int i = 0; i < ans.size(); i++) calc += (pow(2, 31 - i) * ans[i]);         cout << calc <<   n ;       }     }     return 0;   }   