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

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

int n;
unordered_set<int> Hash;

int main() {
    int tip, x;
    in >> n;
    for (int i = 1; i <= n; ++i) {
        in >> tip >> x;
        if (tip == 1)
            Hash.insert(x);
        if (tip == 2)
            Hash.erase(x);
        if (tip == 3)
            out << Hash.count(x) << '\n';
    }
    in.close();
    out.close();
    return 0;
}