#include <iostream>
#include <fstream>
#include <unordered_map>

using namespace std;

ifstream fin("hashuri.in");
ofstream gout("hashuri.out");

unordered_map<int, int> list;

void add(int x) {
    list[x] = x;
}

void del(int x) {
    list.erase(x);
}

void search(int x) {
    gout << list.contains(x) << "\n";
}

int main() {
    short ops_nr;
    int op;
    int elem;

    fin >> ops_nr;
    cout << ops_nr << "\n";

    for (int i = 0; i < ops_nr; ++i) {
        fin >> op >> elem;
        switch(op) {
            case 1:
                add(elem);
                break;
            case 2:
                del(elem);
                break;
            case 3:
                search(elem);
                break;
            default:
                throw runtime_error("Wrong op");
        }
    }

    fin.close();
    gout.close();
    return 0;
}