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

using namespace std;

template<typename T>
class Set {
private:
    const int PRIME_SIZE = 1000001;
    vector<list<T>>* hashTable;

    int hash(T value) const {
        return abs(value % PRIME_SIZE);
    }
public:
    Set() {
        this->hashTable = new vector<list<T>>(PRIME_SIZE);
    }
    ~Set() {
        delete this->hashTable;
    }
    void insert(T value) {
        int index = hash(value);
        for (auto i : hashTable->at(index))
            if (i == value)
                return;
        hashTable->at(index).push_back(value);
    }
    void erase(T value) {
        int index = hash(value);
        for (auto iter = hashTable->at(index).begin(); iter != hashTable->at(index).end(); iter++) {
            if (*iter == value) {
                hashTable->at(index).erase(iter);
                return;
            }
        }
    }
    bool find(T value) const {
        int index = hash(value);
        for (auto i : hashTable->at(index))
            if (i == value)
                return true;
        return false;
    }
};


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

    Set<long long> newSet;

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

    return 0;
}