#include <iostream>
#include <vector>
#include <fstream>
#include <cmath>

using namespace std;

ifstream input("set.in", ios_base::in);
ofstream output("set.out", ios_base::out | ios_base::trunc);

struct Node {
    Node() {
    }

    Node(int value) {
        this->value = value;
    }

    int value;
    Node *next;
};

struct HashTable {
    HashTable() {
        hastTable.assign(SIZE + 3, nullptr);
    }

    int getHash(int value) {
        long a = value * 113 + 145861;
        a %= 6130667;
        a %= SIZE;
        return abs(a);
    }

    void insert(int value) {
        if (!contains(value)) {
            int hash = getHash(value);
            Node *currNode = hastTable[hash];
            if (currNode == nullptr) {
                hastTable[hash] = new Node(value);
            } else {
                while (currNode->next != nullptr){
                    currNode = currNode->next;
                }
                currNode->next = new Node(value);
            }
        }
    }

    bool contains(int value) {
        int hash = getHash(value);
        Node *currNode = hastTable[hash];
        while (currNode != nullptr && currNode->value != value) {
            currNode = currNode->next;
        }
        return currNode != nullptr && currNode->value == value;
    }

    void remove(int value) {
        if (contains(value)) {
            int hash = getHash(value);
            Node *currNodePrev = hastTable[hash];
            if (currNodePrev->next != nullptr) {
                Node *currNode = hastTable[hash]->next;
                while (currNode->value != value) {
                    currNodePrev = currNodePrev->next;
                    currNode = currNode->next;
                }
                if (currNode->next == nullptr) {
                    currNodePrev->next = nullptr;
                } else {
                    currNodePrev->next = currNode->next;
                }
            } else {
                hastTable[hash] = nullptr;
            }
        }
    }

    const int SIZE = 987911;
    vector<Node *> hastTable;
};

int main() {
    string command;
    int value;
    HashTable hashtable;
    while (input >> command) {
        input >> value;
        if (command == "insert") {
            hashtable.insert(value);
        } else if (command == "exists") {
            output << (hashtable.contains(value) ? "true" : "false") << "\n";
        } else if (command == "delete") {
            hashtable.remove(value);
        }
    }
}