#include <fstream>
#include <unordered_set>

using namespace std;

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

int main() {
    int n;
    unordered_set<int> nrSet;
    fin >> n;
    for (int i = 0; i < n; i++) {
        int op, nr;
        fin >> op >> nr;
        switch (op) {
            case 1:
                nrSet.insert(nr);
                break;
            case 2:
                nrSet.erase(nr);
                break;
            case 3:
                fout << nrSet.count(nr) << "\n";
                break;
            default:
                break;
        }
    }
    return 0;
}