#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <set>
#include <math.h>
#include <list>

using namespace std;
typedef long long int lli;

class Set {
private:
    const lli PRIME_SIZE = 1000001;
    vector<list<lli>>* hashTable;

    int hash(lli num) const {
        return abs(num % PRIME_SIZE);
    }
public:
    Set() {
        this->hashTable = new vector<list<lli>>(PRIME_SIZE);
    }

    void insert(lli num) {
        lli index = hash(num);
        for (auto i : hashTable->at(index))
            if (i == num)
                return;
        hashTable->at(index).push_back(num);
    }

    void erase(lli num) {
        lli index = hash(num);
        for (auto iter = hashTable->at(index).begin(); iter != hashTable->at(index).end(); iter++) {
            if (*iter == num) {
                hashTable->at(index).erase(iter);
                return;
            }
        }
    }

    bool find(lli num) const {
        lli index = hash(num);
        for (auto iter = hashTable->at(index).begin(); iter != hashTable->at(index).end(); iter++)
            if (*iter == num)
                return true;
        return false;
    }
};


int main() {
    ifstream ist("set.in");
    ofstream ost("set.out");

    Set newSet;
    string com;
    lli num;
    while (ist >> com >> num) {
        if (com == "insert")
            newSet.insert(num);
        else if (com == "delete")
            newSet.erase(num);
        else
            ost << (newSet.find(num) ? "true" : "false") << endl;
    }

    return 0;
}