#include <iostream>
#include <set>
#include <fstream>

using namespace std;

int main() {
    ifstream in("hashuri.in");
    ofstream out("hashuri.out");

    int n, op, x;
    set<int> hash_set;

    in >> n;

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

        if (op == 1)
            hash_set.insert(x);
        else if (op == 2)
            hash_set.erase(x);
        else if (op == 3)
            out << (hash_set.find(x) != hash_set.end()) << '\n';
    }

    return 0;
}