#include <iostream>
#include <vector>
#include <fstream>
#include <memory>
using namespace std;
struct Node
{
    int hash;
    int key;
    int value;
    Node* next;

    Node(int hash, int key, int value)
	{
		next = NULL;
		this->hash = hash;
		this->key = key;
		this->value = value;
	}
};

struct HashSet
{
    unsigned int MOD;
    vector<Node*> table;

    HashSet()
    {
    	MOD = 96557;
        table.resize(MOD);
    }

    int hash(int x)
    {
        x = x ^ (x >> 16);
        return x;
    }

    Node* get(int key)
    {
        Node* node = table[hash(key) % MOD];
        while (node != NULL)
        {
            if (node->key == key)
            {
                return node;
            }
            node = node->next;
        }
        return NULL;
    }

	bool exists(int key)
	{
	    return (get(key) != NULL);
	}


    void add(int key)
    {
        if (exists(key))
        {
            return;
        }
        int h = hash(key);
        Node* node = new Node(h, key, key);
        node->next = table[h % MOD];
        table[h % MOD] = node;
    }

    void remove(int key)
    {
        int h = hash(key);
        Node* node = table[h % MOD];
        Node* prev_node = NULL;
        while (node != NULL)
        {
            if (node->key == key)
            {
                if (prev_node == NULL)
                {
                    table[h % MOD] = node->next;
                }
                else
                {
                    prev_node->next = node->next;
                    node->next = NULL;
                }
                return;
            }
            prev_node = node;
            node = node->next;
        }
    }
};


int main()
{
    HashSet set;
    while (!cin.eof())
    {
        string op;
        int key;
        cin >> op >> key;
        if (op == "insert")
        {
            set.add(key);
        }
        if (op == "delete")
        {
            set.remove(key);
        }
        if (op == "exists")
        {
            cout << (set.exists(key) ? "true" : "false") << endl;
        }
    }
    return 0;
}