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

int main() {
    ifstream fin("hashuri.in");
    ofstream fout("hashuri.out");
    int n, op, x;
    unordered_set<int> s;
    fin >> n;
    while(n--) {
        fin >> op >> x;
        if(op == 1)
            s.insert(x);
        else if(op == 2)
            s.erase(x);
        else
            fout << (s.find(x) != s.end()) << '\n';
    }
}