#include <bits/stdc++.h>
using namespace std;

int n;
unordered_map<int, bool> m;

int main() {
    cin >> n;
    for (int i = 1; i <= n; ++i) {
        int op, x;
        cin >> op >> x;
        if (op == 1) {
            m[x] = true;
        } else if (op == 2) {
            m.erase(x);
        } else {
            cout << (m.find(x) != m.end()) << "\n";
        }
    }
}