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

ifstream cin("hashuri.in");
ofstream cout("hashuri.out");

set <int> S;
int x, op, n, i;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie();
    cin >> n;

    for(i = 1; i <= n; i++) {
        cin >> op >> x;
        if(op == 1)
            S.insert(x);    ///il adaug in set;
        else if(op == 2)
            S.erase(x); ///il sterg din set;
        else cout << S.count(x) << '\n';    ///verific daca e in set;
    }

    return 0;
}