#include <fstream>
#include <string>
#include <iostream>

using namespace std;

//300007

struct list{
    int element;
    list* next;
};

struct set{
    list* a[300007];
    set(){
        for (int i = 0; i < 300007; i++)
            a[i] = nullptr;
    }

    void Insert(int el){
        list *findEl = a[abs(el) % 300007];
        list *prevEl = findEl;
        while (findEl != nullptr && findEl->element != el) {
            prevEl = findEl;
            findEl = findEl->next;
        }
        if (findEl == nullptr) {
            list *newElement = new list;
            newElement->next = nullptr;
            newElement->element = el;
            if (prevEl == nullptr) {
                a[abs(el) % 300007] = newElement;
            }
            else {
                prevEl->next = newElement;
            }
        }
    }

    int Exists(int el) {
        list *findEl = a[abs(el) % 300007];
        while (findEl != nullptr && findEl->element != el) {
            findEl = findEl->next;
        }
        if (findEl != nullptr && findEl->element == el)
            return 1;
        else
            return 0;
    }

    void Delete(int el){
        list* findEl = a[abs(el) % 300007];
        list* prevEl = a[abs(el) % 300007];
        int flag = 1;
        while(findEl != nullptr && findEl -> element != el){
            prevEl = findEl;
            findEl = findEl -> next;
        }
        if (findEl != nullptr && findEl -> element == el){
            if (findEl == a[abs(el) % 300007])
                a[abs(el) % 300007] = findEl -> next;
            else
                prevEl -> next = findEl -> next;
            delete(findEl);
        }
    }
};


int main(){
    ifstream in;
    ofstream out;
    in.open("set.in");
    out.open("set.out");
    set Set;
    while(!in.eof()){
        string com;
        int element;
        in >> com;

        if (com.size() == 0)
            break;
        in >> element;
        if (com == "insert"){
            Set.Insert(element);
        }
        if (com == "exists"){
            if(Set.Exists(element))
                out << "true\n";
            else
                out << "false\n";
        }
        if (com == "delete"){
            Set.Delete(element);
        }
    }
    in.close();
    out.close();
    return 0;
}