#include <fstream>
#include <set>

std::set<int> hash;

int main()
{
    std::ifstream fin("hashuri.in");
    std::ofstream fout("hashuri.out");

    int n;
    fin >> n;

    for (int i = 0; i < n; ++i) {
        int op, x;
        fin >> op >> x;
        if (op == 1) hash.insert(x);
        else if (op == 2) hash.erase(x);
        else fout << hash.count(x) << '\n';
    }

    return 0;
}