#include <string>
#include <iostream>

using namespace std;

const int SIZE = 1e6;

struct Node {
    int data = 0;
    Node *next = nullptr;
    bool is_used = false;

    void insert(int num) {
        if (this->is_used) {
            if (this->data != num) {
                insert_to_next(num);
            }
        } else {
            this->is_used = true;
            this->data = num;
        }
    }

    void insert_to_next(int num) {
        if (!next) {
            next = new Node;
        }
        next->insert(num);
    }

    bool exists(int num) {
        if (this->equals(num)) {
            return true;
        }
        if (this->next) {
            return this->next->exists(num);
        }
        return false;
    }

    void remove(int num) {
        if (this->equals(num)) {
            this->is_used = false;
        } else if (this->next) {
            this->next->remove(num);
        }
    }

    bool equals(int num) {
        return this->is_used && this->data == num;
    }
};

struct Set {
    Node *hash_to_node[SIZE + 10]{};

    Set() {
        for (int hash = 0; hash < SIZE + 5; ++hash) {
            hash_to_node[hash] = new Node;
        }
    }

    void insert(int num) {
        int hash = Set::get_hash(num);
        hash_to_node[hash]->insert(num);
    }

    bool exists(int num) {
        int hash = Set::get_hash(num);
        return hash_to_node[hash]->exists(num);
    }

    void remove(int num) {
        int hash = Set::get_hash(num);
        this->hash_to_node[hash]->remove(num);
    }

    static int get_hash(int num) {
        return abs(num) % SIZE;
    }
};


int main() {
    Set set;
    string s;
    int num;

    while (cin >> s >> num) {
        if (s == "insert") {
            set.insert(num);
        } else if (s == "exists") {
            cout << (set.exists(num) ? "true" : "false") << endl;
        } else if (s == "delete") {
            set.remove(num);
        }
    }

    return 0;
}