#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
struct element{
    int value = 0;
    bool isNClear = false;
};
element set_[1000000];

bool add(element* arr, int x){
    int i = x % 1000000;
    int check = 0;
    while(arr[i].value != 0){
        if((size_t)i >= sizeof(*arr)/sizeof(arr[0])){
            i = -1;
        }
        i++;
        check++;
        if((size_t)check > sizeof(*arr)/sizeof(arr[0]))
            return false;

    }

    arr[i].isNClear = true;
    arr[i].value = x;
    return true;

}
size_t find(element* arr, int x){
    int i = x % 1000000;
    int check = 0;
   // cout << arr[i].isNClear;
    while(arr[i].value != x && arr[i].isNClear){
        if((size_t)i >= sizeof(*arr)/sizeof(arr[0])){
            i = -1;
        }
        i++;
        check++;
       // cout << check << " " << sizeof(*arr)/sizeof(arr[0]);
        if((size_t)check > sizeof(*arr)/sizeof(arr[0]))
            return -1;
    }
    if(arr[i].value == x)
        return i;
    else
        return -1;

}
void deleteel(element* arr, int x){
    int i = x % 1000000;
    int check = 0;
    while(arr[i].value != x && !arr[i].isNClear){
        if((size_t)i >= sizeof(*arr)/sizeof(arr[0])){
            i = -1;
        }
        i++;
        check++;
        if((size_t)check > sizeof(*arr)/sizeof(arr[0]))
            return ;
    }
    arr[i].value = 0;
}
void show(element* arr){
    cout << "\n";
    for(size_t i = 0; i<1000000; i++){
        if(arr[i].value != 0)
            cout << arr[i].value << ",";
    }
    cout << "\n";
}
int main()
{
    ifstream inp("set.in");
    ofstream out("set.out");

    while(true){
        string operathion;
        inp >> operathion;
      //  cout << operathion;
        if(operathion == "insert"){
            int x;
            inp >> x;
            if(find(set_, x) == -1)
                add(set_, x);
            operathion = "";

        }
        else if(operathion == "exists"){
            int x;
            inp >> x;
            int result = find(set_, x);
            if(result == -1){
                out << "false\n";

            }
            else{
                out << "true\n";
            }
            operathion = "";

        }
        else if(operathion == "delete"){
            int x;
            inp >> x;
            deleteel(set_, x);
            operathion = "";
        }
        else{
            return 0;
        }
    }


    return 0;

}