#include <set>
#include <fstream>

using namespace std;

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

int main() {
    set<int> s;

    int n;
    cin >> n;

    for (int i = 0; i < n; i++) {
        int op, x;
        cin >> op >> x;
        switch(op) {
            case 1:
                s.insert(x);
                break;
            case 2:
                s.erase(x);
                break;
            case 3:
                cout << (s.find(x) != s.end()) << endl;
                break;
        }
    }

    return 0;
}