#include <fstream>
#include <unordered_set>
using namespace std;

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

unordered_set<int> S;

int main() {
    int n;
    fin >> n;

    for (int i = 1; i <= n; ++i) {
        int op, x;
        fin >> op >> x;

        if (op == 1) {
            S.insert(x);
        } else if (op == 2) {
            S.erase(x);
        } else {
            fout << (S.find(x) != S.end()) << '\n';
        }
    }
    return 0;
}